4.1 ____________________________________________________________________ BIOS and UEFI 4.1.1 BIOS and UEFI Firmware is special program code stored in flash memory, closely tied to the basic functions of specific hardware. Computer firmware helps initialize components on the motherboard so they can load the main operating system. For many years, computers used basic input/output system (BIOS) firmware. Most motherboards now use unified extensible firmware interface (UEFI) instead. UEFI supports 64-bit CPU operation, has a graphical user interface (GUI) with mouse support, offers networking at boot, and provides better boot security. A computer with UEFI can also boot in legacy BIOS mode. You can configure system settings through the firmware setup program, accessed by pressing a key during the boot process, usually when the computer vendor's logo appears. Common keys include Esc, Del, F1, F2, F10, or F12. Bootup access to system firmware setup A Dell BIOS boot screen shows the Dell logo, PowerEdge T310, BIOS Revision 1.12.0 and several options at the top. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description Note: Modern computers can boot quickly. If you miss the key prompt, you can Shift-click the Restart button from the Windows logon screen to access UEFI boot options. In a legacy BIOS setup program, you navigate using the keyboard arrow keys. Pressing Esc generally returns to the previous screen. When closing setup, you can choose to exit and discard changes or exit and save changes. Sometimes, this is done with a key (Esc versus F10, for instance), but more often, there is a prompt. You can also reload default settings if needed. A BIOS setup program Dell Inc. Power Edge T 310, BIOS Version 1.12.0 screen displays BIOS setup program. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description UEFI setup programs use a graphical interface and have mouse support, though some advanced menus may still require keyboard navigation. A UEFI setup program ASUS BIOS Utility in E Z Mode shows system details, boot priority, LCD, USB Port, Storage, hardware monitor, access, and property. Screenshot used with permission from ASUSTek Computer Inc. ____________________________________________________________________ 4.1.2 Boot and Device Options One key system setup parameter is the boot option sequence or boot device priority, which determines the order in which the system firmware searches devices for a boot manager. Boot parameters Dell Inc. Power Edge T 310, BIOS Version 1.12.0 screen displays boot parameters. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description Typical choices include: Fixed disk (Hard Disk Drive or Solid State Drive): For drives connected via Serial Advanced Technology Attachment (SATA), it's recommended to connect the boot disk to the lowest-numbered port. In modern systems, SSDs using NVMe (Non-Volatile Memory Express) via the M.2 or PCIe (Peripheral Component Interconnect Express) interface are often used as boot drives, offering faster speeds than SATA SSDs. Optical drive (CD/DVD/Blu-ray): If performing a repair or installation from optical media, you may need to set the optical drive as the highest priority. Universal Serial Bus: Most modern systems can boot from a USB drive formatted as a boot device. USB booting is commonly used for operating system (OS) installations and recovery utilities. Network/PXE (Preboot Execution Environment): Boots via the network adapter by retrieving boot instructions from a configured server. Boot order configuration Dell Inc. Power Edge T 310, BIOS Version 1.12.0 screen displays boot order configuration. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description Interactive Mobile Placeholder This content is only available on larger screen sizes. Please revisit this page on a larger device. ____________________________________________________________________ 4.1.3 USB Permissions System firmware allows you to enable or disable controllers and adapters, including USB ports. Since USB connections can pose security risks, the firmware setup program may let you control USB permission by enabling or disabling individual or all USB ports. Using UEFI setup to configure permissions for USB and other external interfaces ASUS BIOS Utility in Advanced Mode. Security tab is selected. Screenshot used with permission from ASUSTek Computer Inc. Description ____________________________________________________________________ 4.1.4 Fan Considerations Proper maintenance and configuration of cooling fans are crucial for optimal system performance and longevity. Regularly clean fans to prevent dust accumulation, which can obstruct airflow and lead to overheating, potentially damaging components. Ensure that airflow is balanced, with an equal amount of air entering and exiting the system. Position fans to facilitate effective airflow based on thermodynamics, avoiding configurations that push hot air downward. Most cooling fans can be controlled through system settings, typically found under menus like Cooling, Power, or Advanced. Options usually include: Balanced: A standard setting for general use. Cool: Runs fans at higher speeds for maximum cooling. Quiet: Reduces fan speed, allowing for higher temperatures. Fanless: Disables fans, relying on passive cooling. Custom: Allows for personalized fan speed settings. You can also set the minimum temperature at which fans start to cool the system. Duty cycle settings control the frequency of power pulses to the fan; a higher percentage results in faster fan operation. The setup program will display the current temperature from probes near each fan connector. Note: There are many third-party utilities that can access these settings and monitors from within the OS. Temperature Monitoring There are two ways to monitor a computer's temperature: manually or through a third-party application. Manual Monitoring: Restart your computer and enter the BIOS/UEFI settings by pressing a specific key during boot, usually F2, Delete, F12, or ESC. In the UEFI menu, look for an entry related to monitoring or sensors to view real-time readings, including CPU temperature. Third-Party Applications: These applications monitor computer temperatures through sensors that collect data. Many sensors have preset thresholds that trigger alerts when temperatures exceed safe limits. ____________________________________________________________________ 4.1.5 Boot Passwords and Secure Boot A boot password requires user authentication before the operating system loads. Different systems support various authentication methods, with typically two main passwords available: Supervisor/Administrator/Setup/BIOS Password: Restricts access to the system's BIOS/UEFI setup program. User/System Password: Locks the entire system until authentication is provided, preventing any actions until the firmware initializes the system. Note: You must tell everyone who uses the computer the password, which weakens the security considerably. This option would be used only on workstations and servers that aren't used for interactive logon, such as computers running monitoring or management software. Configuring system security Dell Inc. Power Edge T 310, BIOS Version 1.12.0 screen displays system security. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description Secure boot is a UEFI feature that protects against malware by ensuring only trusted, digitally signed bootloaders are used. The system firmware checks the operating system's bootloader against pre-loaded cryptographic keys to verify its integrity. If the bootloader is modified or unsigned, it will not be allowed to run. Many modern systems require UEFI (Unified Extensible Firmware Interface) with Secure Boot enabled for security and compatibility with newer operating systems. Note: Keys from vendors like Microsoft (Windows and Windows Server) and Linux distributions (Fedora, openSUSE, and Ubuntu) are pre-loaded. You can add or remove keys for other bootloaders through the system setup software. Secure boot can also be disabled if needed. ____________________________________________________________________ 4.1.7 Trusted Platform Modules Encryption protects secure data by scrambling it in such a way that it can only be decrypted using the correct decryption key. This security relies heavily on protecting the decryption key. UEFI-based systems provide secure storage for these keys, often using hardware-based solutions like the Trusted Platform Module (TPM). Note: Encryption encodes data using a key to ensure confidentiality. Many cryptographic processes also use hashing. Hashing generates a unique code (hash) from data, allowing verification of data integrity without revealing the original data. Hashes are used to compare data, but unlike encryption, the original data cannot be recovered from the hash. Trusted Platform Module A trusted platform module (TPM) is hardware that securely stores digital certificates, cryptographic keys, and hashed passwords. Each TPM chip has a unique, unchangeable endorsement key, establishing a root of trust. During boot, the TPM compares hashes of key system data (such as firmware, boot loader, and OS kernel) to ensure they haven't been tampered with. The TPM provides superior security by storing cryptographic keys in tamper-resistant hardware, isolating them from the OS and applications, which are more vulnerable to malware and unauthorized access. Its integration with firmware and the OS ensures secure boot processes and key protection, preventing extraction or compromise, unlike keys stored in ordinary apps or files. The TPM's secure storage area can be used by disk encryption programs like Windows BitLocker to store their keys. TPMs can be enabled, disabled, or reset via the system setup program (BIOS/UEFI) and managed from the operating system. Configuring a TPM Dell Inc. Power Edge T 310, BIOS Version 1.12.0 screen displays configuration of T P M. Reproduced with permission of Dell Copyright © Dell 2025 (2025). All Rights Reserved. Description Hardware Security Module A removable USB thumb drive can be used to store cryptographic keys. This is useful if the computer does not support TPM, as a recovery mechanism if the TPM is damaged, or if a disk needs to be moved to another computer. A secure USB key or thumb drive used to store cryptographic material is referred to as a hardware security module (HSM). "Secure" means that the user must authenticate with a password, personal identification number (PIN), or fingerprint to access the keys stored on the module. ____________________________________________________________________ ____________________________________________________________________ 4.2 Power and Disk Issues ____________________________________________________________________ 4.2.1 Troubleshoot Power Issues Computer components need a constant, stable supply of power to run. If the computer won't start, it is likely due to a power problem. If the PC suddenly turns off or restarts, power issues are a common cause. When a computer is switched on, the power supply unit (PSU) converts AC input voltage (VAC) to DC voltage (VDC). DC voltage powers the motherboard components and peripheral devices. The PSU supplies 12V power immediately, causing the fans and hard disks to spin up. It then tests its 5V and 3.3V supplies. Once stable, it sends a power good signal to the processor. To diagnose no power symptoms, check if the LEDs on the front panel are lit and if you can hear the fans. Power issues might arise from a faulty PSU, incoming electricity supply, power cables/connectors, or fuses. To isolate the cause of no power, try the following tests: Check other equipment: Ensure other devices in the area are working to rule out a power circuit fault or a blackout. Test the wall socket: Plug a known-good device, like a lamp, into the wall socket. If it doesn't work, the socket is faulty. Contact an electrician. Verify PSU connections: Ensure the PSU is properly connected to the PC and wall socket, and all switches are in the "on" position. Try another power cable: There may be an issue with the plug or fuse. Check the plug's wiring and fuse resistance with a multimeter or swap with a known good fuse. Disconnect extra devices: Remove devices like a plug-in graphics card. If this solves the problem, the PSU may be underpowered, or one of the devices is faulty. Test the PSU: If safe, use a multimeter or power supply tester to check the PSU. Technician working with a power supply tester A technician wearing gloves tests a power supply unit using a digital power supply tester connected to multiple cables on a workstation. Image by Konstantin Malkov @123RF.com Note: You must take appropriate safety measures before testing a live power supply. PC power supplies are NOT user serviceable. Never remove the cover of a power supply. If you still cannot identify the fault, then the problem is likely to be a faulty motherboard or power supply. If you suspect the power supply, do not leave it on longer than necessary or unattended. Watch for external signs like smoke or fire and turn it off immediately if you notice any unusual sights, smells, or noises. ____________________________________________________________________ 4.2.2 Troubleshoot POST Issues Once the CPU has been given the power good signal, the system firmware performs a power-on self-test. The POST is a diagnostic program implemented in the system firmware that checks the hardware components required to boot the computer. Note: On modern computers, the POST happens very quickly to improve boot times, so you are unlikely to see any POST messages. The PC is likely to be configured to show a logo screen and will only display messages if there is an error. If power is present (e.g., you hear the fans spinning) but the computer does not start, shows a blank screen, and there are no beeps from the internal speaker, it is likely either a display issue or the POST procedure is not executing. Assuming the display is not the issue, try the following: Ask what has changed—If the system firmware has been updated and the PC has not booted since then, the system firmware update may have failed. Use the reset procedure. Check cabling and connections—Especially if maintenance work has just been performed, ensure all cables and adapter cards are correctly seated. An incorrectly oriented storage adapter cable or a poorly seated adapter card can stop POST from running. Correct any errors, reset adapter cards, and then reboot the PC. Check for faulty interfaces and devices—A faulty adapter card or device may halt POST. Remove one device at a time to identify the faulty component, or remove all non-essential devices and add them back one by one. Check the PSU—Even if the fans are receiving power, there may be a fault preventing the power good signal from being sent to the CPU, stopping POST. Check for a faulty CPU or system firmware—If possible, replace the CPU chip with a known good one or update the system firmware. Note: Some motherboards have jumpers to configure modes (such as firmware recovery) or processor settings. Incorrect jumper settings can prevent the computer from booting. If the computer does not work after being serviced, check that the jumpers have not been changed. If POST runs but detects a problem, it generates an error message. If the fault prevents the computer from displaying anything on the screen, the error is often indicated by beep codes. Use resources such as the manufacturer's website to determine the meaning of the beep code. The codes for the original IBM PC are listed in this table. Code Meaning 1 short beep Normal POST -system is OK. Most modern PCs are configured to boot silently, however. 2 short beeps POST error -error code shown on screen. No beep Power supply, motherboard problem, or faulty onboard speaker. Continuous beep Problem with system memory modules or memory controller. Repeating short beeps Power supply fault or motherboard problem. 1 long, 1 short beep Motherboard problem. 1 long, 2 or 3 short beeps Video adapter error. 3 long beeps Keyboard issue (check that a key is not depressed). Note: Some PCs will not boot if a key is stuck. Check that nothing is resting on the keyboard. If the board is clogged with dust or sticky liquid, clean it using approved products, such as swabs and compressed air blowers. Interactive Mobile Placeholder This content is only available on larger screen sizes. Please revisit this page on a larger device. ____________________________________________________________________ 4.2.3 Troubleshoot Boot Issues After completing the POST, the system searches for boot devices in the order specified in the boot sequence. If the first device is not found, it attempts the next one, such as checking for a USB drive or network boot. If no bootable device is found, an error message is displayed, and the process halts. If the system is booting from the wrong device, verify that removable drives do not have media interfering with the boot process, and ensure the boot order is correct. If a fixed disk is not detected: Power Check: Ensure the drive is powered. Look for an activity LED, listen for the drive spinning up, or verify power connectors are secure. Data Connections: Inspect data cables for damage and verify they are properly connected. UEFI/BIOS Settings: Confirm the drive is enabled in UEFI/BIOS and that settings like Secure Boot or SATA mode (AHCI, RAID) are correctly configured. M.2/NVMe Drives: For modern drives, ensure they are properly seated and detected in UEFI/BIOS. ____________________________________________________________________ 4.2.4 Troubleshoot Boot Sector Issues If power and cabling issues are ruled out, suspect a problem with the device's boot sector and files. Corruption can occur due to disk faults, power failures, incorrect installation of multiple operating systems, or malware, preventing the disk from booting. Boot Information Formatting: MBR and GPT There are two ways of formatting boot information: MBR and GPT. Master Boot Record (MBR): In the legacy MBR scheme, the MBR is located in the first sector of the partitioned disk. It holds information about disk partitions and contains code pointing to the active boot sector. The boot sector, located immediately after the MBR or in the first sector of each partition, describes the partition's file system and contains code to boot the operating system. This includes Boot Configuration Data (BCD) for Windows or boot managers like GRUB or LILO for Linux. Only one primary partition can be marked as active for booting. GUID Partition Table (GPT): GPT is not limited to a single sector and provides more robust and flexible partitioning compared to MBR. It identifies partitions and OS boot loaders, offering enhanced reliability. Damage to the MBR or GPT partition records can cause boot errors like "Boot device not found," "OS not found," or "Invalid drive specification." If malware caused the issue, the best solution is to use your antivirus software's boot disk option. This includes a scanner to detect the malware and tools to repair the boot sector. If a recovery disk is unavailable, use the repair options provided by the OS setup disk. When encountering boot issues, if power and cabling problems are ruled out, the device's boot sector and files may be at fault. Corruption can arise from disk faults, power failures, incorrect installation of multiple operating systems, or malware, preventing the disk from booting. Additionally, a blank screen during boot can indicate issues with the boot process or display connections. The troubleshooting steps include: Check Display Connections: Ensure that the monitor is properly connected to the computer and powered on. A loose or faulty cable can result in a blank screen. Inspect Boot Errors: Damage to the MBR or GPT partition records can cause boot errors such as "Boot device not found," "OS not found," or "Invalid drive specification." Malware Solutions: If malware is suspected, use your antivirus software's boot disk option, which includes a scanner to detect malware and tools to repair the boot sector. Repair Options: If a recovery disk is unavailable, utilize the repair options provided by the operating system setup disk to address boot sector issues. ____________________________________________________________________ 4.2.5 Troubleshoot OS Errors and Crash Screens If a boot device is found, the boot sector code is loaded into memory and takes over from the system firmware, loading the rest of the operating system files. Common symptoms of errors after this point are usually due to software or device driver issues rather than hardware problems. One of the most common symptoms of serious faults in a Windows system is the appearance of the Blue Screen of Death (BSOD). This proprietary crash screen indicates issues such as system memory faults, hardware device or driver problems, or OS file corruption. The BSOD can be caused by: Faulty or incompatible device drivers Corrupted system files Defective hardware components Overheating or power supply issues To troubleshoot a BSOD: Use a camera to scan the QR code displayed on the screen for more information. The error is logged in the System log with "BugCheck" as the source. Use the first hex value (e.g., 0x0a) from the event description to search for more information online. If you have a support contract, a memory dump is generated for further analysis. Blue screen of death (BSOD) preventing a Windows PC from booting A Windows blue screen error with a sad face, a Q R code, and text Your P C ran into a problem and needs to restart. We'll restart it for you. Screenshot courtesy of Microsoft. Note: A blue screen is a crash screen specific to Windows. macOS shows a spinning pinwheel (spinning wait cursor) for catastrophic failures. Linux displays a kernel panic or a "Something has gone wrong" message. ____________________________________________________________________ 4.2.6 Troubleshoot Drive Availability A hard disk drive (HDD) is more prone to mechanical failure either within the first few months or after several years of use (wear and tear). Solid-state drives (SSDs) are generally more reliable but have a limited lifespan due to the wear on memory cells from repeated writes. Power loss during write operations can cause data corruption or hardware damage for both types of drives. When a drive is failing, it may exhibit these common symptoms: Unusual noise (HDD): A healthy HDD emits a low-level noise when accessing data. Loud grinding, clicking, or scraping sounds often indicate mechanical failure. No light-emitting diode (LED) status/activity: If disk activity lights are off, the system or the drive may not be powered. If the individual drive is faulty, check connections or power supply. For drives in RAID arrays, this could indicate a missing or failed array. Constant LED activity (Disk Thrashing): Continuous disk activity could indicate insufficient system RAM, causing excessive paging to the disk. It could also be a result of a faulty software process, malware, or a failing disk. Bootable device not found: If a system fails to boot, it might point to file corruption or a faulty drive. This may also occur if a RAID controller fails to detect one or more drives in the array, leading to the array going "missing." Missing drives in OS: If the drive doesn't appear in tools like File Explorer or command-line interfaces, check if it has been initialized, partitioned, and formatted. If not detected by tools like Windows Disk Management, suspect hardware or cable/connector faults. Read/Write failure: Errors like "Cannot read from the source disk" are signs of bad sectors on HDDs or bad blocks on SSDs. Running diagnostic tools like chkdsk can identify if bad sectors or blocks are increasing, indicating imminent failure. Audible alarms: Many enterprise-level drives and RAID controllers include audible alarms to alert users of drive or array failure. These alarms may indicate hardware issues or missing drives in an array, requiring immediate attention. Blue screen of death (BSOD): Severe drive issues can cause system crashes, particularly due to file corruption or read/write errors. This could result in a system stop error (BSOD). If you encounter any of these symptoms, it's important to back up data immediately and replace the drive to prevent data loss. ____________________________________________________________________ 4.2.7 Troubleshoot Drive Reliability and Performance In addition to symptoms that you can detect by observing system operation, most fixed disks have a self-diagnostic program called Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.). S.M.A.R.T can alert the operating system if a failure is detected. If you suspect a drive is failing or experience performance issues like extended read/write times, run advanced diagnostic tests. Most disk vendors provide utilities for testing drives, and there may also be system diagnostics programs supplied with the computer. Using system diagnostics software to test a hard drive A diagnostic tool window shows custom tests for a hard drive. Screenshot courtesy of Microsoft. Description You can also use Windows utilities to query SMART and run manual tests. Viewing SMART information via the SpeedFan utility Speed Fan 4.51 shows S.M.A.R.T. attributes of a hard disk. Screenshot courtesy of Microsoft. Description These tests can detect damage to the storage mechanisms and report statistics such as input/output operations per second (IOPS). If performance metrics are lower than the vendor's baseline measurements, the device is likely faulty. If metrics are similar to the benchmark, slow read/write access may be due to other system performance issues, such as: Application load and general system resource issues File fragmentation (on HDDs) Limited remaining capacity Extended read/write times can also occur due to failing sectors (HDDs) or blocks (SSDs). Data loss or corruption means files stored in these locations cannot be opened or may disappear. When bad sectors or blocks are detected, the disk firmware marks them as unavailable for use. If there is file corruption on a hard disk and no backup, you can attempt to recover data using a recovery utility. Using file recovery software to scan a disk Active at file recovery interface displays local devices on the left and a table on the right. Screenshot courtesy of Microsoft. Description Note: File recovery from an SSD is not usually possible without highly specialized tools. ____________________________________________________________________ 4.2.8 Troubleshoot RAID Failure Redundant Array of Independent Disks (RAID) is configured to protect data against the failure of a single disk. Data is either mirrored to a second drive or recorded with parity information across multiple drives to enable recovery from a device failure. RAID can be implemented using hardware controllers or operating system features. The redundant storage is presented as a volume, which can be partitioned and formatted in the OS as one or more drives. There are two main scenarios for RAID failure: Device Failure: If one of the devices in the array fails, the volume will be listed as "degraded," but the data will still be accessible, and it should continue to function as a boot device if configured to do so. Note: RAID 0 has no redundancy. If one of the disks fails, the volume will stop working. RAID 0 is used in scenarios where speed is prioritized over reliability. Array Failure: Most desktop-level RAID solutions can tolerate the loss of only one disk, so it should be replaced as soon as possible. If the array supports hot swapping, the new disk can be inserted into the computer or disk chassis. The array can then be rebuilt using the RAID configuration utility (for hardware RAID) or an OS utility (for software RAID). The rebuilding process will likely severely affect performance as the controller writes multiple gigabytes of data to the new disk. RAID errors using the configuration utility. This volume is missing one of its disks A screen from the Dell PERC H 200 RAID utility shows volume and device details along with a table at the bottom. Description Note: When hot swapping, ensure you do not remove a healthy disk, as this could cause the array to fail. Disk failure is usually indicated by a red LED. Always back up data beforehand. Troubleshooting Steps Unavailable Volume or "array missing": If the volume is not available, either more disks have failed than the array can tolerate, or the controller has failed. If the boot volume is affected, the OS will not start. Use the latest backup or file recovery solutions if too many disks have failed. Controller Failure: If the controller fails, data on the volume should be recoverable, though there may be file corruption if a write operation was interrupted. Install a new controller or import the disks into another system. Boot Process Issues: Use the RAID configuration utility to verify the status. If you cannot access the utility, the controller likely failed. Boot message indicating a problem with the RAID volume. Press Ctrl+C to start the utility and troubleshoot A Boot message indicates a problem with the RAID volume. Description ____________________________________________________________________ ____________________________________________________________________ 4.3 System and Display Issues ____________________________________________________________________ 4.3.1 Troubleshoot Component Issues Symptoms like system lockups, random shutdowns, continuous rebooting, OS blue screen/Kernel panic errors, and application crashes can be challenging to diagnose. These issues are often caused by software problems, disk/file corruption, or malware. Diagnostic Steps: Eliminate Software Issues: Ensure that software, disk/file corruption, and malware are not the causes. Identify Patterns: Determine if the problem is truly intermittent or follows a pattern. For example, if errors occur after the PC has been running for a while, it could indicate a thermal issue. Check Power Supply: Verify that the power supply is providing stable voltages to the system. Suspect Hardware: If the power supply is not the issue, consider problems with memory, CPU, or the motherboard. Use diagnostic test programs provided by the vendor, which are often run from the firmware setup utility rather than the OS. Observe Physical Symptoms: If no diagnostic utilities are available, look for physical symptoms to identify issues with the motherboard, RAM, or CPU. Interactive Mobile Placeholder This content is only available on larger screen sizes. Please revisit this page on a larger device. Settings Full Screen Previous Chapter Play Video Next Chapter 00:00 1. Introduction to Troubleshooting Hardware Issues Interactive Script ____________________________________________________________________ 4.3.2 Overheating Excessive heat can easily damage the sensitive circuitry of a computer. If a system feels hot to the touch, check for overheating issues. Unusual odors, such as a burning smell or smoke, usually indicate overheating, likely from the power supply. Shut down the system immediately and investigate. Dust-clogged vents can also cause burning smells. Note: CPUs and other components heat up during operation. Handle internal components carefully to avoid burns. Other techniques for diagnosing and correcting overheating issues include the following: Temperature Sensors: Most systems have internal temperature sensors accessible via driver or management software. Use vendor documentation to ensure the system operates within acceptable limits. CPU Fan: Ensure the CPU fan is working properly. Cooling is vital for processor performance and lifespan. Overheating can cause crashes or reboots. Check if the fan's power cable is connected, if the fan is jammed or clogged, or if it is too small. A fan from an older CPU may not be suitable for an upgraded processor. Heat Sink: Verify that the heat sink is properly fitted and snug against the processor. Clean and replace old thermal paste if necessary to help lower the processor's temperature. Blanking Plates: Use blanking plates to cover holes in the back or front of the PC case. Uncovered holes can disrupt airflow and reduce cooling effectiveness. Environment: Ensure the room is not unusually warm or dusty and that the PC is not near a radiator or in direct sunlight. Thermal problems can also cause loose connectors, components to move in their sockets, or circuit board defects like hairline cracks to widen and break connections. Some faults can be detected by visual inspection. ____________________________________________________________________ 4.3.3 Physical Damage Actual Physical damage to a computer system typically affects peripherals, ports, and cables. Damage to other components is more likely if the unit has been in transit. Inspect the unit closely for case damage; even a small crack or dent may indicate a fall or knock that could have caused internal damage. If a peripheral device is not working, examine the port and cable ends for bent, broken, or dirty pins and connectors. Check the cable length for any damage. Motherboard issues are rare but possible. Be aware of the following: Electrostatic Discharge (ESD), Electrical Spikes, or Overheating: These can damage the motherboard's soldered chips and components. Careless Insertion: Pins on integrated connectors can be damaged by improper insertion of plugs and adapter cards. Dirt and Chip Creep: Errors may be caused by dirty contacts or chip creep, where an adapter works loose from its socket over time due to temperature changes. Visible signs of damage include: Liquid Spills: Look for signs of liquid damage or dust clogging fans or the keyboard. Scorch Marks and Capacitor Swelling: A "blown" component may leave scorch marks. Swollen or bulging capacitors, which regulate electricity flow, may indicate damage or manufacturing defects. If the motherboard shows physical damage, diagnostic software is essential to confirm the problem. Testing with "known good" components is often too time-consuming and expensive. Investigate any environmental issues or maintenance procedures that could be the root cause of the error. ____________________________________________________________________ 4.3.4 Troubleshoot Performance Issues Performance issues are challenging to diagnose due to their varied causes. Use a structured approach to identify the source of sluggish performance: Check for overheating—High temperatures can cause the CPU and other components to throttle performance to avoid damage. Monitor temperature sensors and fan speeds. If they are high, consider cleaning the computer or upgrading the cooling system. Check for misconfigurations—If sluggish performance occurs after a new build, upgrade, or maintenance, verify the compatibility of new components with the motherboard. For instance, a memory upgrade might disable dual-channel mode, reducing performance. Always ask, "What has changed?" when diagnosing issues. Verify the problem—Performance issues can stem from compute, storage, or networking functions. Use diagnostic tests to compare the CPU, system memory, fixed disk, and network adapter performance against known baselines. Quantifying "sluggish" performance and isolating it to a specific subsystem helps identify the cause. If performance is insufficient, consider upgrading one or more subsystems. Note: A bottleneck occurs when an underperforming component slows down the entire system. For example, a PC with a fast CPU, dedicated graphics, and ample memory may still be sluggish if it's using an HDD, as SSDs provide much faster performance. While SSDs are now standard, modern bottlenecks can arise from improper NVMe drive configurations, latency issues, or bandwidth limitations, such as PCIe lanes not supporting optimal speeds (e.g., PCIe 3.0 vs. 4.0). Rule out software/configuration/networking issues—Users might describe performance as sluggish due to configuration problems. For example, a computer might seem slow due to a faulty network login script, not a hardware issue. Rule out operating system and application issues before assuming hardware problems. Use built-in or third-party diagnostic tools to verify component performance. If diagnostics show no hardware issues, suspect a software or configuration problem. ____________________________________________________________________ 4.3.5 Troubleshoot Inaccurate System Date/Time Accurate timekeeping is crucial for computers, as incorrect date and time settings can disrupt network authentication and make scheduled tasks like backups unreliable. The real-time clock (RTC) tracks the date and time, powered by a coin-cell lithium battery (usually CR2032) when the computer is off. RTC coin cell battery on the motherboard A motherboard with the circular R T C coin cell battery labeled. Image ©123RF.com If the time in the system setup is incorrect, it may signal a failing RTC battery, which should be replaced with the same type. This battery is often called the "CMOS battery" because older systems stored settings in CMOS (complementary metal-oxide semiconductor) RAM. However, modern systems use NVRAM (non-volatile random-access memory) or flash memory for configuration data, so the battery mainly supports the RTC. Note: Modern systems frequently use Network Time Protocol (NTP) to sync time with network clocks. ____________________________________________________________________ 4.3.6 Troubleshoot Missing Video Issues If no image is displayed on the monitor or projector, first ensure the display device is plugged in and turned on. Verify that the monitor is not in standby mode by pressing a key or cycling the power. Use the monitor's controls to adjust the image or select the correct input source. An incorrect input source is a common issue; for example, if there is no image, make sure the monitor is set to the HDMI port connected to the computer, not an empty DVI port. These settings are accessible via the on-screen display (OSD) menus, operated by buttons on the monitor case, where you can also adjust brightness, color/contrast, and power-saving settings. Physical Cabling Issues If the display is powered on and the input source is not the issue, check the cable and connectors between the video card and monitor. Ensure the cable is securely connected at both ends and is not loose, stretched, or crimped. Verify that the cable specification matches the application requirements; for instance, a basic HDMI cable may not support 4K resolution, which requires a High-Speed rated cable. Another common issue is cable and port compatibility, especially with newer technologies like HDMI 2.1, DisplayPort 1.4, or USB-C. Using the appropriate cable and port can help avoid connection issues and ensure optimal display performance. Note: To rule out cable problems, use the "known good" technique by substituting with another cable. Alternatively, test the monitor with a different PC to determine whether the issue lies with the display unit or the input source. Burnt-Out-Bulb Issues A video projector is a large-format display device used for presentations and meetings, projecting images onto a screen or wall through a lens system. Projectors use various imaging technologies such as cathode ray tube (CRT), liquid crystal display (LCD), and digital light processing (DLP). Unlike PC monitors that use small backlights or LED arrays, projectors rely on high-intensity bulbs to project images. A DLP projector A projector with ventilation grills, a lens on the front, and control buttons on the top surface. Image ©123RF.com Projector bulbs have a limited lifespan and will eventually need to be replaced. Signs of a failing bulb include dimming images and a possible bulb health warning on the projector. A completely failed bulb, known as a "burnt-out bulb," may produce a popping sound and show visible scorch marks or a broken filament. Note: Projector bulbs get extremely hot during use and become fragile when heated. Always allow the projector to cool down fully before attempting to handle or replace the bulb to avoid damage or injury. Modern projectors increasingly use LED or laser light sources, which last significantly longer and reduce the need for frequent bulb replacements, making "burned-out bulb" issues less common in newer models. Intermittent Projector Shutdown Issues Intermittent projector shutdown is typically caused by overheating. To troubleshoot, ensure the fan is working properly, verify that the ventilation system is clear of dust and debris, and confirm that the vents are not blocked. Also, check that the ambient temperature is within the projector's operating range. If overheating is not the issue, check for loose connector cables that may disrupt power or signal, and ensure the bulb is securely installed, as an improperly installed bulb can cause unexpected shutdowns. Additionally, make sure the projector's firmware is up to date, as some models may have software-related shutdowns that can be resolved with updates. ____________________________________________________________________ 4.3.7 Troubleshoot Video Quality Issues Video quality issues, such as artifacts or glitches, can result from problems with the display or the input source (e.g., video card). Below are common issues and steps for troubleshooting: Dim image: Check the On-Screen Display (OSD) to adjust brightness and contrast. Power-saving modes or features like adaptive brightness or eye-saving mode may reduce brightness automatically, triggered by ambient light sensors or specific times of day. If the image is barely visible, the backlight may have failed, and the display may need repair or replacement. Fuzzy image: A fuzzy image is often due to a mismatch between the output resolution and the display's native resolution. For example, if a monitor's native resolution is 1920x1080 but the video card is set to 1024x768, the image will appear blurry. To resolve, adjust the resolution in the operating system or update the video driver. Flashing screen: Check the video cable and connectors to ensure they are securely attached. Flickering or flashing could also result from failing backlight components or internal circuitry. Other signs of failure include bands, lines, or bright spots. If so, the display may need repair. Note: A faulty or overheating video card can also cause flashing. Try connecting the monitor to another computer to isolate the issue. Dead pixels: Stuck (constantly bright) or dead (black) pixels can occur in flat-panel displays. Stuck pixels may be fixed using pixel cycling software or by gently tapping the screen with a soft object. Dead pixels usually cannot be repaired. Check your warranty for replacement options. Display burn-in: Burn-in happens when a static image is displayed for too long, leaving a ghost image on the screen. OLED and plasma displays are more prone to burn-in than TFT/LED screens. Prevent burn-in by using a screen saver or enabling the display's auto-off function during inactivity. Note: A TFT/LED monitor uses an LED backlight to illuminate the image. In an OLED, each pixel provides its own illumination. Incorrect color display: For digital art production, it is crucial to calibrate the display to match scanning devices and print output. Color calibration involves adjusting screen and scanner settings to balance color input and output using a color profile. Utilize the Color Management applet in Control Panel, along with test card color patterns and spectrophotometers, to define and verify this profile. Display Color Calibration utility in Windows 10 A screen displays the How to adjust gamma section of the Display Color Calibration window. Screenshot courtesy of Microsoft. Description Color glitches, such as purple or green horizontal lines or unexpected color changes, are often caused by a faulty or loose connector or low-quality cabling. Try replacing the cable. If the issue persists, there may be a hardware fault in the monitor or graphics adapter. Audio issues: HDMI and DisplayPort can transmit both video and audio, while DVI and VGA do not. If you're not getting audio from built-in speakers, check power, connections, and volume controls. Verify that the correct audio output is selected in the operating system and that volume settings are appropriate. Sizing issues: If the screen appears stretched, compressed, or has black bars around the edges, adjust the display settings on your computer to match the monitor's native resolution and use the monitor's on-screen display (OSD) menu to fit the image to the screen. Additionally, ensure that the correct video drivers are installed and updated. Distorted image: If the screen appears wavy or shows geometric warping, like pincushion effects, check for interference from nearby electronic devices, secure all cable connections, and ensure the display settings match the monitor's native resolution. For a CRT (Cathode Ray Tube), adjust the pincushion settings and consider replacing a potentially faulty cable. ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ /ENDOFCHAPTER