An external monitor can be blank while Windows itself continues running. Start with the display chain before recovery tools.
Protect your files first
Back up important files when possible. If the drive is encrypted, locate the BitLocker recovery key before recovery changes. Stop if storage appears to be failing or this is a work or school managed PC.
What to record
Monitor input, cable, dock, other display, and whether Windows detects the screen.
The exact message, Windows version, and whether the desktop still opens matter more than a guess based on the symptom name.
Try these safer checks
Check cables, input selection, and display settings; then use the dock or PC maker’s official driver support.
Change one thing at a time. After each check, see whether the same symptom returns and write down what changed.
When to stop and get help
Do not reset Windows for a single external display without ruling out the monitor path.
If this is a work or school device, contact its administrator before changing managed settings.
Keep track of your checks
This checklist stays in this browser session. It is not sent to WinErrors.