HOW TO USE: Work through each section top-to-bottom. Check each box as you confirm it’s OK. Stop when you find the culprit.
① DISPLAY & CABLES — Check first (free, 2 min)
Monitor power light is ON and cable is seated firmly
Try a different monitor or TV via HDMI/DisplayPort
Disconnect all USB drives & dongles, then reboot
Check for bent/broken pins on video cable connectors
Test with known-good power cable / surge protector
② GPU (GRAPHICS CARD) — Reseat before replacing
Power off, reseat GPU firmly in PCIe slot (feel the click)
Plug monitor into GPU port, NOT the motherboard port
Reconnect PCIe power connector(s) from PSU to GPU
③ RAM (MEMORY) — Most common cause of no-POST
Remove all RAM sticks; clean gold contacts with eraser
Test with ONE stick in slot A2 (check manual), then swap
Listen for POST beep codes (1 long beep = RAM error)
④ BIOS, CMOS & POWER SUPPLY
Remove CMOS battery 30 sec, reinstall to reset BIOS
Use PSU tester — check 12V / 5V / 3.3V rails are in spec
Try known-good PSU if rails fail or fan won’t spin
⑤ ADVANCED DIAGNOSIS — If steps 1-4 don’t resolve it
Boot from USB (Hiren’s BootCD) to rule out OS issues
Run MemTest86 for 2 full passes to test RAM stability
CrystalDiskInfo: check SSD/HDD health & reallocated sectors
Check Event Viewer → Windows Logs → System for errors
QUICK SYMPTOM GUIDE
No power at all
→ PSU, power button, wall outlet
Fans spin, no display
→ RAM, GPU, BIOS — follow sections 1-4
Beeps on startup
→ RAM error — test 1 stick at a time
Random freezes / BSODs
→ RAM (MemTest86) or failing SSD
PC shuts off under load
→ Overheating — clean fans & repaste CPU
Slow / stuttering
→ Full SSD (keep 15% free) or malware
Blue screen MEMORY_MGMT
→ Bad RAM stick — swap/test individually
Clicking / grinding noise
→ HDD dying — back up data immediately
Corrupted Windows files
→ Run: sfc /scannow in admin CMD
FREE DIAGNOSTIC TOOLS
MemTest86 memtest86.com
RAM errors — bootable USB, runs before Windows
CrystalDiskInfo crystalmark.info
Drive SMART health — catches failing drives early
HWMonitor cpuid.com
Real-time temps, voltages & fan RPM
Hiren’s BootCD hirensbootcd.org
Full offline repair toolkit — no Windows needed
Malwarebytes malwarebytes.com
Malware scan — free tier available
Speccy ccleaner.com/speccy
Full system snapshot — CPU, RAM, drive, temps
⚠ WHEN TO CALL A PRO
Motherboard or CPU damage (burn marks, bent pins)
Liquid damage — do NOT power on, call first
Data recovery needed (clicking hard drive)
Laptop screen replacement or keyboard repair
Persistent issues after completing this checklist
Diagnosis fee: $40-$75 (credited toward repair)
SAFE TEMPERATURE RANGES
| Component | Normal | Warning | Critical |
|---|---|---|---|
| CPU (idle) | 30-50C | 75C | 90C+ |
| CPU (load) | 60-80C | 85C | 95C+ |
| GPU | 50-75C | 85C | 95C+ |
| SSD (NVMe) | 40-60C | 70C | 80C+ |