Symptoms
- Power LED is lit (steady or blinking)
- Screen stays completely black
- Computer seems to be running (fans spinning, other lights on)
- Monitor was fine before a restart, update, or being unplugged
Likely causes
- CommonVideo cable not connected or connected looselyThis is the most common and easiest cause to check.
- CommonMonitor set to the wrong input sourceIf the cable is fine but plugged into an input the monitor isn't displaying, the screen stays black.
- PossibleComputer not fully powering on despite fan noiseA PC can spin fans without successfully completing boot, producing no video.
- PossibleGraphics card failure or seating issue (desktops)A loose or failed GPU stops video output while the rest of the system still powers on.
What to do
- Check and firmly reseat the video cable at both the monitor and computer ends.
- Press the monitor's Source/Input button and cycle through all available inputs.
- Listen for your computer's normal startup sounds or beeps, which can indicate it's trying to boot but failing before video output.
- For desktop PCs, open the case (after powering off and unplugging) and check that the graphics card is fully seated in its slot.
- If you have integrated graphics, try connecting the monitor to the motherboard's video port instead of the graphics card, or vice versa, to isolate the source.
- Test the monitor with another device, like a laptop, to confirm it can display an image at all.
Tools and parts
- Screwdriver (if reseating a desktop GPU)
When to call a pro
If the monitor shows an image from another device but the computer never produces video on any monitor, the graphics card or motherboard likely needs professional diagnosis.
Safety
Use caution
Always power off and unplug the computer before opening the case to check internal components.