A blue screen (BSOD) is Windows stopping itself because it can no longer run safely. On current versions of Windows 11, the screen is black and titled as an unexpected restart rather than blue, but it means the same thing. The key to fixing it is the stop code shown on screen, plus noticing when the crashes happen.
1. Write down the stop code
The screen shows a code in capital letters, such as MEMORY_MANAGEMENT. Snap a photo with your phone if you can. If you missed it, Reliability Monitor (step 4) keeps a record.
2. Common stop codes and what they usually mean
These are general tendencies, not diagnoses. The same code can have different causes on different PCs.
| Stop code | Common causes |
|---|---|
| IRQL_NOT_LESS_OR_EQUAL, DRIVER_IRQL_NOT_LESS_OR_EQUAL | A faulty driver, sometimes RAM |
| MEMORY_MANAGEMENT | RAM or a driver |
| PAGE_FAULT_IN_NONPAGED_AREA | RAM, a driver, or security software |
| SYSTEM_SERVICE_EXCEPTION | A driver or corrupted system files |
| CRITICAL_PROCESS_DIED | A core Windows process ended; often file corruption |
| VIDEO_TDR_FAILURE | Graphics driver |
| INACCESSIBLE_BOOT_DEVICE | Windows can't reach the boot drive |
| WHEA_UNCORRECTABLE_ERROR | Hardware: CPU, RAM, overheating or overclocking |
| DPC_WATCHDOG_VIOLATION | A driver or storage firmware |
3. Undo recent changes
Think about what changed just before the crashes started.
- Remove any new hardware (RAM, graphics card, USB devices) and test.
- Uninstall recently added apps or drivers.
- If a driver update came first, open Device Manager, right-click the device, and choose Properties > Driver > Roll Back Driver.
- If it began right after a Windows update, you can remove it in Settings > Windows Update > Update history > Uninstall updates.
4. Check Reliability Monitor
- Search the Start menu for View reliability history, or press Win + R and type
perfmon /rel. - Click the red X icons on the timeline.
- Open entries like "Windows stopped working" or hardware errors and select View technical details to see the stop code.
Because it also shows which apps and drivers were installed each day, it's great for spotting what triggered the problem.
5. Look at minidump files
After a crash, Windows usually saves a small dump file in C:\Windows\Minidump. Install WinDbg from the Microsoft Store, open the .dmp file, and run !analyze -v; it often names the driver that was involved. If that feels too technical, attach the file when asking for help on Microsoft's community forums or with your PC maker's support.
6. Test your memory
- Search for Windows Memory Diagnostic (or run
mdsched.exe). - Choose Restart now and check for problems (recommended).
- After the test, Windows boots and shows the result in a notification.
If it reports errors, test one memory stick at a time or consider replacing the RAM.
7. Check system files, the disk and temperatures
In an admin Command Prompt, run DISM /Online /Cleanup-Image /RestoreHealth followed by sfc /scannow. Then check the drive with our disk health guide, and if crashes happen under load, see the CPU temperature guide.
8. If Windows won't start
After repeated crashes, Windows opens the recovery environment automatically. Under Troubleshoot > Advanced options you'll find Startup Repair, System Restore, and Startup Settings (for Safe Mode). Our Windows repair guide walks through each.
FAQ
It happened once and never again.
A single crash isn't usually cause for concern. Keep Windows and drivers up to date and watch whether it repeats.
It only crashes during games.
Graphics drivers, overheating and power supply issues are the usual suspects. Do a clean install of the GPU driver from the maker's site and check temperatures.
Should I use a "PC error fixer" app?
We don't recommend apps that promise to fix blue screens for a fee. Everything above uses free tools built into Windows.