CompTIA A+ Core 1 (220-1201)Hardware and Network TroubleshootingMedium

A technician is troubleshooting a client's desktop computer that randomly reboots and occasionally displays a 'blue screen of death' (BSOD) with varying error codes. The system has been running fine for over a year without any hardware changes. Which component is the MOST likely cause of these symptoms?

  1. ANetwork Interface Card (NIC)
  2. BGraphics Processing Unit (GPU)
  3. CHard Disk Drive (HDD)
  4. DPower Supply Unit (PSU)
Show answer & explanation

Correct answer: D. Power Supply Unit (PSU)

Random reboots and BSODs with varying error codes, especially after a period of stable operation without hardware changes, strongly suggest an unstable power supply. A failing PSU can deliver inconsistent voltage, leading to system instability.

Why the other options are wrong

  • A. A NIC issue would primarily affect network connectivity, not cause random system reboots or BSODs.
  • B. A GPU issue usually manifests as display artifacts, driver crashes, or no video output, not general system instability with random reboots.
  • C. An HDD issue typically causes boot failures, file corruption, or system freezes, not random reboots and varying BSODs.

Failing Power Supply Unit (PSU)

A power supply that is no longer delivering stable and consistent power to system components, leading to unpredictable behavior.

  • Can cause random reboots, system crashes, and varying BSOD errors.
  • Symptoms are often intermittent and difficult to diagnose.
  • May also manifest as components failing to power on or system not booting.

Memory trick: Unstable power makes a computer's mind go blank.

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