Understanding the Blue Screen of Death

A BSOD means Windows hit an unrecoverable error. Don’t panic — the stop code tells you exactly what went wrong.

Step-by-Step Diagnosis

1. Identify the Stop Code

The blue screen shows a code like IRQL_NOT_LESS_OR_EQUAL. Write it down.

2. Boot into Safe Mode

If Windows won’t boot normally:

  1. Power on, wait for Windows logo, hold power button to force shutdown.
  2. Repeat 3 times — Windows enters Automatic Repair.
  3. Choose Troubleshoot > Advanced Options > Startup Settings > Restart.
  4. Press 4 or F4 for Safe Mode.

3. Run System Repair Tools

sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
chkdsk C: /f /r

Most Common BSOD Stop Codes

Stop CodeCommon CauseFix
IRQL_NOT_LESS_OR_EQUALFaulty driver accessing wrong memoryUpdate/roll back the driver shown in crash dump
KERNEL_DATA_INPAGE_ERRORBad disk sector or failing HDD/SSDRun chkdsk /f /r; replace drive if SMART shows errors
PAGE_FAULT_IN_NONPAGED_AREABad RAM or corrupt driverRun Memory Diagnostic; test with MemTest86
SYSTEM_SERVICE_EXCEPTIONAntivirus conflict or corrupt system fileSFC + DISM; disable third-party antivirus
DRIVER_POWER_STATE_FAILUREDevice driver can’t handle sleep/wakeUpdate chipset + GPU drivers; disable fast startup
CRITICAL_PROCESS_DIEDEssential Windows process crashedSFC + DISM; if persistent, in-place upgrade repair
UNEXPECTED_STORE_EXCEPTIONStorage driver or fast startup issueDisable fast startup; update storage drivers
KMODE_EXCEPTION_NOT_HANDLEDHardware or driver problemIdentify driver from dump; replace if hardware
WHEA_UNCORRECTABLE_ERRORHardware failure (CPU, RAM, or motherboard)Check temperatures; test RAM; may need hardware replacement
DPC_WATCHDOG_VIOLATIONSSD firmware or storage controllerUpdate SSD firmware and AHCI/NVMe drivers

Diagnostic Tools

ToolPurposeHow to Run
SFCScan/fix corrupt system filessfc /scannow (admin CMD)
DISMRepair Windows imageDISM /Online /Cleanup-Image /RestoreHealth
chkdskFix disk errorschkdsk C: /f /r (reboot required)
WinDbgAnalyze crash dump filesOpen .dmp from C:\Windows\Minidump\
Memory DiagnosticTest RAMmdsched.exe
MemTest86Thorough RAM test (boots from USB)Download and boot
Event ViewerCheck system logs around crash timeeventvwr.msc > Windows Logs > System
Driver VerifierStress-test drivers to find faultsverifier (use carefully, can cause more BSODs)

Quick Fixes by Symptom

SymptomMost Likely CauseQuick Fix
BSOD after Windows UpdateBad updateUninstall recent update from Safe Mode
BSOD during gamingGPU driver or overheatingUpdate GPU driver; check temps with HWMonitor
BSOD on boot every timeCorrupt boot filesStartup Repair or bootrec /fixmbr
BSOD after installing new RAMIncompatible or bad DIMMRemove new RAM; test sticks individually
BSOD after driver installBad driverRoll back in Device Manager from Safe Mode
Random BSODs, different codesBad RAMRun MemTest86 overnight

Troubleshooting

ProblemSolution
Can’t boot at allUse Windows installation USB > Repair > Command Prompt
SFC finds errors but can’t fixRun DISM first, then SFC again
BSOD persists after all fixesIn-place upgrade repair (keeps files and apps)
Need the crash dump but can’t find itCheck C:\Windows\Minidump\ or %SystemRoot%\MEMORY.DMP

Summary

  • Read the stop code — it’s your most valuable diagnostic clue.
  • SFC + DISM + chkdsk fix most software-caused BSODs.
  • Driver issues cause ~70% of BSODs — update or roll back.
  • RAM failures cause random BSODs with different codes — test with MemTest86.