Start with the cables and ports

A monitor that shows no picture almost always means a loose or damaged cable, a wrong port, or a power issue — not a broken graphics card or motherboard. Check these things first, in this order, because they take two minutes and solve the problem nine times out of ten.

Look at the cable running from your monitor to your PC. On one end it plugs into the monitor; on the other it plugs into the back of your tower or laptop. Unplug both ends completely, wait five seconds, and plug them back in firmly until you hear or feel a click. Do the same with the monitor's power cable — unplug it from the wall outlet, wait five seconds, and plug it back in. Then turn the monitor on using its power button (usually on the front or bottom edge). If you see a picture, you are done.

If you still see nothing, look at which port the cable is plugged into on your PC. Modern PCs have multiple video ports on the back: HDMI (a flat rectangular port), DisplayPort (similar but with a notch), or VGA (a port with three rows of small holes). Your monitor cable should be plugged into one of these. If it is plugged into a different port — one that looks like a USB port or has a different shape — unplug it and try a different video port instead.

Key Takeaways

  • Reseat both ends of the video cable and the monitor's power cable by unplugging and replugging them firmly.
  • Make sure the cable is plugged into a video port (HDMI, DisplayPort, or VGA) on the back of your PC, not a USB or audio port.
  • If your PC has both integrated graphics and a separate graphics card, the monitor may need to be plugged into the graphics card port instead of the motherboard port.
  • Check that your monitor is powered on, set to the correct input, and not in sleep mode by pressing its buttons or moving your mouse.
  • If the monitor shows "No Signal" or a blue screen, the PC is likely running but not sending video — restart it or check the BIOS settings.

Identify which graphics port your PC uses

Many PCs have two sets of video ports: one built into the motherboard (called integrated graphics) and one on a separate graphics card. Your monitor cable must be plugged into the correct one, or you will see nothing even though the PC is running.

Look at the back of your PC tower. If you see two or three video ports clustered together near the top or bottom, and another set of video ports further down, your PC has both. The lower set usually belongs to a graphics card. Try unplugging your monitor cable from whichever port it is in now and plugging it into a port on the graphics card instead. If you see a picture, that was the problem.

If you are not sure which is which, look for a card that sticks out from the back of the tower — it will be wider than the motherboard and have ports on its bracket. That is your graphics card. Plug the monitor into one of its ports. If the PC still shows no picture, try the motherboard ports instead.

Check the monitor itself

Your monitor has its own power button and settings. If the PC is running but the monitor shows a black screen, the monitor itself may be off, in sleep mode, or set to the wrong input.

Press the power button on the monitor — it is usually on the front or bottom edge, sometimes marked with a circle or a line. Look for a light on the monitor that turns on or changes color. If nothing happens, check that the power cable is plugged into the wall outlet and that the outlet has power (plug a lamp into it to test).

If the monitor is on but the screen is black, press any key on your keyboard or move your mouse to wake it from sleep mode. If the screen still shows nothing, look for a button labeled "Input" or "Source" on the monitor. Press it and cycle through the options until you see a picture. Some monitors default to the wrong input when they restart.

If the monitor shows "No Signal" or "No Input" in white text on a blue or black background, the monitor is on and working — it is just not receiving video from the PC. This means the cable is loose, plugged into the wrong port, or the PC is not sending video. Go back and check the cable connection and port again.

Restart your PC and check the BIOS

If the monitor shows "No Signal" but the PC appears to be running (you hear the fan, see lights, or hear it beeping), restart the PC. Hold down the power button on the tower for ten seconds until it shuts off completely, wait ten seconds, then press the power button once to turn it back on. Let it boot all the way up — this can take a minute or two — and see if a picture appears.

If restarting does not work, the PC may be stuck in the BIOS setup screen or the graphics drivers may not be loading. Restart the PC again. As soon as you press the power button, watch for text on the screen that says "Press DEL to enter Setup" or "Press F2 to enter BIOS" or something similar. If you see this message, press the key it tells you to press. You will enter a menu with white text on a blue background.

In the BIOS menu, look for a setting called "Integrated Graphics" or "Onboard Video" or "Primary Graphics Adapter". If it is set to "Disabled" or "Off", change it to "Enabled" or "On" using the arrow keys and Enter. Save and exit (usually by pressing F10 and then Y). The PC will restart, and you should see a picture this time.

Test with a different cable or monitor

If you have tried everything above and still see no picture, the cable or monitor itself may be damaged. Borrow a different video cable from a friend or a second monitor if you can, and try it with your PC.

If a different cable works, your original cable is bad and needs to be replaced — they cost between five and twenty dollars depending on the type. If a different monitor works, your original monitor is broken and will need repair or replacement. If neither a different cable nor a different monitor fixes the problem, the issue is likely inside your PC — a loose graphics card, a failed power supply, or a motherboard problem — and you should take it to a repair shop for diagnosis.

When to seek in-person help

If you have worked through all the steps above and still have no picture, or if you are not comfortable opening your PC tower to check the graphics card, a local computer repair shop can diagnose the problem in under an hour. Bring your PC, monitor, and cables with you. The shop can test each part separately and tell you whether the problem is the cable, the monitor, the graphics card, or something else inside the tower.

Many shops offer free diagnostics or charge a small fee (usually ten to thirty dollars) that goes toward the repair if you decide to fix it there. If the problem is just a loose cable or a wrong setting, they can fix it on the spot for little or no cost.

Frequently Asked Questions

Why does my monitor say "No Signal" when my PC is clearly on?

The PC is running but not sending video to the monitor. This usually means the cable is loose, plugged into the wrong port, or the monitor is set to the wrong input. Reseat the cable at both ends, make sure it is plugged into a video port (HDMI, DisplayPort, or VGA), and check that the monitor is set to the correct input using its buttons.

My PC has two sets of video ports. Which one should I use?

If your PC has a separate graphics card, use the ports on the graphics card (usually the lower set on the back of the tower). If you only see one set of ports, or if the graphics card ports do not work, try the motherboard ports instead. You can only use one set at a time.

Can a bad monitor cable cause no picture?

Yes. Video cables can fray, bend, or develop loose connections inside. If reseating the cable does not work, try a different cable. If a different cable works, your original cable is damaged and should be replaced.

What if my monitor turns on but stays completely black?

Press any key or move your mouse to wake it from sleep mode. If that does not work, press the monitor's "Input" or "Source" button and cycle through the available inputs. If the monitor shows "No Signal" instead of black, the cable is loose or plugged into the wrong port.

Do I need to open my PC tower to fix this?

Not usually. Most no-picture problems are solved by reseating cables, checking ports, and restarting the PC. You only need to open the tower if you want to reseat the graphics card or check for loose connections inside, which is optional if the steps above do not work.