- Check for loose electrical and VGA cables. Remove the electric cord from the back of the monitor, then put it back in place. Remove the VGA cable from the computer and monitor and put it back in place. Make sure the connection is tight. If you're using a cable extender, remove it.
- Plug the monitor's electric cord into a different outlet. If you're using a UPS or surge protector, plug it directly into a wall outlet.
- Attach the monitor to a different computer. If the monitor still doesn't work, replace the monitor's cable. Make sure the cable is less than 5 feet long. If it still doesn't work, the monitor will need to be replaced or repaired. If it works with no problem on the other computer, troubleshoot your video card.
- Unplug your computer from the monitor and power outlet. Remove the cover. Pull the video card out of the slot on the system board. Push it back into place. Be sure the connection is secure.
- Put the CD that came with your video card into your computer's CD-ROM drive. Follow the directions to reinstall the video card drivers. Download a new version of the drivers from the manufacturer's website if necessary.
- Right-click a blank area of your Desktop. Choose "Properties" from the display menu. Click the "Settings" tab. Try different screen resolutions to resolve the problem.
- Determine whether the problem is caused by electrical interference. Electrical interference will make the monitor appear jumpy or wavy. Move any speakers, radios, fans or other items that can cause electrical interference away from the monitor.
Test a computer monitor -
- Check to make sure your monitor is on! Some monitors have more than one power button or switch - check to make sure they're all switched on.
- Check for disconnected monitor power cable connections. Your monitor might be working fine and your only problem may be a loose or unplugged monitor power cable.
- Check for disconnected monitor data cable connections. Again, your monitor might be turning on without a problem but no information can get to it because the cable that connects your monitor to your computer is disconnected or loose.
- Turn the monitor's brightness and contrast settings completely up. Your monitor might be showing information but you just can't see it because these display settings are too dark.
Test that your computer is working correctly by connecting a different monitor that you are certain is working properly to your PC. Your monitor may be working fine but your computer might not be sending information to it.
- If the new monitor you connected does not show anything either, proceed to Step 6.
- If the new monitor you connected does show information from your computer, proceed to Step 7.
- Determine why your computer isn't sending information to your monitor. Since neither monitor works, you now know that the computer is not sending information to the monitor. In other words, you've proven that your computer is the reason that nothing shows up on your monitor. Chances are your original monitor is working fine.
- Test your original monitor with a monitor data cable that you know is working. It's possible that the monitor itself is working properly but it can't receive information from the computer because the cable that connects the monitor to the PC is no longer working.
- Replace the monitor.