What to do after a blue screen (stop code) error

A blue screen means Windows hit a problem it couldn’t recover from and restarted to protect your data. A single crash is usually nothing to worry about. Repeated crashes need attention.

Symptoms

• A blue (sometimes black) screen says “Your device ran into a problem and needs to restart”.
• The PC restarts unexpectedly, and you may lose unsaved work.

Cause

Most often:

• A faulty or out-of-date driver, often graphics, network or a docking station.
• Recently added hardware or a USB device.
• Failing memory or disk.
• A very full system drive.

Fix

1. Write down the stop code

The screen shows a Stop code such as IRQL_NOT_LESS_OR_EQUAL, and sometimes What failed (a file name like nvlddmkm.sys). Take a photo; it’s the most useful clue.

2. Remove anything new

Unplug recently added devices (USB drives, docks, new hardware) and see whether the crashes stop.

3. Install updates

Open Settings › Windows Update. Install everything, including Optional updates (drivers), and restart.

4. Check free space

Keep at least 10–15% free on drive C:. See Free up disk space in Windows.

5. Check Device Manager

Right-click Start › Device Manager. Devices with a yellow warning icon need a driver update or reinstall.

If that didn’t work

• If Windows won’t start normally, start in Safe Mode and remove the last app or driver you installed.
• Use System Restore to go back to a point before the crashes began: search Create a restore point, then choose System Restore.

When to call us

• The PC crashes more than once a week, or always with the same stop code.
• The stop code mentions memory, disk or CRITICAL_PROCESS_DIED. Hardware may be failing, so back up now.
• For IT staff: the crash details are logged as event 1001 (BugCheck).