PC Troubleshooting Cheatsheet
PC Troubleshooting Cheatsheet
Symptoms, causes, and diagnostic tools for common hardware failures.
No Power / No Boot
| Check PSU rocker switch | Must be ON (I) ߀” easy to knock off during cable work |
| Reseat front panel header | Power button pins misaligned ߀” most common cause of no-POST |
| Reseat RAM | Remove and firmly reinsert ߀” one loose DIMM stops all boot |
| Clear CMOS | Remove mobo battery 30s or use CLRTC jumper ߀” resets BIOS to defaults |
| Test PSU (paperclip test) | Short PS_ON (green) to ground (black) on 24-pin ߀” fan should spin |
Beep Codes (AMI BIOS)
| 1 short | POST passed successfully |
| 3 long | RAM not detected ߀” reseat or replace |
| 1 long + 2 short | GPU not detected ߀” reseat GPU, check PCIe power |
| 5 short | CPU error ߀” reseat CPU, check for bent pins |
| Continuous beeps | Power issue or RAM ߀” check all power connectors |
Diagnostic Tools
| MemTest86 | Bootable USB RAM tester ߀” run overnight for thorough test |
| CrystalDiskInfo | S.M.A.R.T. drive health ߀” reallocated sectors > 0 means imminent failure |
| HWiNFO64 | Real-time sensors ߀” CPU/GPU temps, voltages, fan speeds |
| FurMark | GPU stress test ߀” identifies instability under full load |
| Event Viewer | Windows ߆’ WinKey+X ߆’ Event Viewer ߆’ Windows Logs ߆’ System for BSOD details |
Common BSOD Codes
| MEMORY_MANAGEMENT | Faulty or unstable RAM |
| WHEA_UNCORRECTABLE_ERROR | CPU/RAM/PSU instability; hardware defect or overclocking issue |
| CRITICAL_PROCESS_DIED | OS corruption or failing storage drive |
| IRQL_NOT_LESS_OR_EQUAL | Driver conflict or RAM issue |
| SYSTEM_SERVICE_EXCEPTION | Driver error ߀” update or roll back recently changed drivers |