Symptoms
- Monitor shows 'No Signal' even though the PC appears to be running
- Monitor works fine with a different cable or input source
- Problem started after a cable change, monitor swap, or GPU driver update
- Monitor briefly shows a signal, then drops it
Likely causes
- CommonCable plugged into the wrong port on the monitor or GPUMonitors often have multiple inputs, and the wrong one can be selected.
- CommonFaulty or loose HDMI/DisplayPort cableCables fail internally without visible signs of damage.
- CommonMonitor set to the wrong input sourceEasy to overlook if the monitor has several inputs and buttons.
- PossibleGraphics card driver issue after an updateA bad driver update can occasionally cause output problems.
- PossibleFaulty graphics card port or the card itselfTesting a different port or cable narrows this down.
What to do
- Confirm the monitor's input source is set to match the port the cable is plugged into.
- Try a different, known-good HDMI or DisplayPort cable.
- Try a different port on both the graphics card and the monitor if either has more than one.
- Test the monitor with a different device (like a laptop) to rule out the monitor itself.
- Boot into Safe Mode or reinstall the graphics driver if the problem started after a driver update.
- If no combination of cable, port, or device produces a signal, the graphics card's output may have failed.
Tools and parts
- Spare HDMI or DisplayPort cable
When to call a pro
If a different monitor, cable, and port all fail to show a signal, the graphics card likely needs professional testing or replacement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.