Why Windows stops
A blue screen is a protective stop rather than an ordinary freeze. Windows deliberately halts after detecting a critical error that could damage hardware or system files. The stop code explains the fault that caused it.
Step 1 of 6
In this guide
Read the stop code
Read the stop code
At the bottom of the error screen, look for Stop Code: or What failed:. Write down the text, or photograph it with your phone.
Examples include VIDEO_TDR_FAILURE, CRITICAL_PROCESS_DIED and PAGE_FAULT_IN_NONPAGED_AREA. Having that code to hand helps speed up troubleshooting.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Use Safe Mode if you can’t boot up
Use Safe Mode if you can’t boot up
If Windows won't start normally, open the recovery menu. Turn the computer on and use your brand's key:
- HP: tap F11 repeatedly.
- Lenovo: with the computer off, press the Novo button (a small pinhole button, usually on the side or next to the power button), then choose System Recovery.
- Dell / Alienware: tap F12 to open the boot menu, choose SupportAssist OS Recovery, then open the three-dot menu and choose Windows recovery.
- ASUS: hold F9 (F12 on some models) as you turn it on.
- Acer: press Alt + F10 at the Acer logo.
- MSI: tap F3 at the MSI logo.
In the recovery menu, choose Troubleshoot > Advanced options > Startup Settings > Restart. When the list of options appears, press 4 to start in Safe Mode.
If you're asked for a BitLocker recovery key, our guide shows where to find your BitLocker recovery key.
Don't choose a reset or restore option in the recovery tools without contacting us first. Some of them erase your files.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Undo recent updates or software changes
Undo recent updates or software changes
Once you reach your desktop again, whether through a normal start or Safe Mode, work through the following three fixes. A recent computer change is almost always behind a blue-screen error.
- Remove a new app or second antivirus if you installed one just before the trouble began.
- If Windows was just updated, open Settings > Windows Update > Update history > Uninstall updates and remove the latest update.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Review the device drivers
Review the device drivers
A code containing VIDEO, or a filename ending in .sys, indicates a conflict between a device driver and Windows.
- Right-click Start and select Device Manager.
- For an entry marked with a yellow warning triangle, right-click the device, choose Update driver and then Search automatically.
- If the errors began after a graphics update, find the graphics card in Display adapters. Right-click it and select Properties, open the Driver tab and select Roll Back Driver.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Scan for damaged system files
Scan for damaged system files
Damage to a critical system file from a virus or an improper shutdown will cause Windows to blue screen.
- Search Windows for cmd, then right-click Command Prompt and select Run as administrator.
- Enter sfc /scannow and press Enter. Allow it to reach 100% as it repairs damaged files.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Check for failing hardware
Check for failing hardware
Repeated crashes with varying codes can point to a failing component inside the computer.
- Run the computer maker’s hardware check, such as Lenovo Vantage. Our frequent system crashes guide explains that check.
- Disconnect a recently added external drive, mouse, keyboard or printer. A faulty accessory can trigger an immediate stop error.
Restart and use the computer as normal. If the blue screen doesn't come back, you can stop here.
Book IT supportFrequently asked questions
Which part of the error should I record?
Keep the Stop Code text and any What failed entry. A written note or photo gives us the message to work from.
When do I use the Safe Mode section?
Use that section when the computer will not boot normally. The common-fixes section follows once you have reached the desktop, normally or through Safe Mode.
What recent software changes does the guide cover?
It covers a newly installed app, an additional antivirus, a recent Windows update and a graphics-driver update.
Where is the graphics-driver rollback control?
In Device Manager, find the graphics card under Display adapters, open its Properties and use the Driver tab’s Roll Back Driver control.
What hardware checks come last?
The final section covers the manufacturer’s hardware check and recently attached accessories such as an external drive, mouse, keyboard or printer.
