How to fix No Input Signal error message

Updated: 05/21/2018 by Computer Hope

An image of a black computer screen.If your computer monitor is displaying the error message "No Input Signal," follow the steps in the sections below.

Tip: This document is for troubleshooting the "no input signal" message when connecting a monitor to a desktop computer. If you are using a laptop, see our steps on connecting a monitor to a laptop.

Note: To connect to a TV, see our page on how to connect a computer to a TV or projector.

Computer not transmitting signal

Make sure the computer has power. If the computer has turned off, it will not be transmitting a signal and cause the "no input signal" message.

Monitor not connected properly

Verify that the monitor is properly connected in the back of the monitor, as well as to the back of the computer. The monitor video cable will connect to the back of your computer using either a VGA connector or DVI connector. The pictures below are an example of a VGA cable and the connector on the video card.

VGA cable and connector

If the monitor appears to be connected properly, verify the monitor cable is not loose by disconnecting the cable from the back of the monitor and then reconnect the cable. It's also a good idea to rock the cable back and forth to make sure it's not just loose.

Tip: When disconnecting the cable, make sure none of the cable's pins are bent by examining the end of the cable. If any of the cable's pins are bent or broken, the cable may be defective and should be replaced.

Next, disconnect the monitor cable from the back of the computer and then reconnect the cable. When connecting the cable to the computer, ensure the cable connection is tight. With a VGA style connector, like the one shown above, this cable has screws that can be tightened to hold the connector in place.

Tip: Some computers may have onboard video, as well as an expansion video card. When working with this type of computer, you'll have two different connections for your monitor on the back of your computer. If you see more than one VGA or DVI connector and the monitor is not working, try the other connector.

Incorrect input selected

Some newer monitors are capable of connecting to a computer using a VGA or DVI connector. For these types of monitors, the correct input selection needs to be used. Access the settings on the monitor using the buttons on the front or bottom edge of the monitor. Look for options to select the type of connector being used, either VGA or DVI, and select the correct input being used for your monitor to connect to your computer.

Bad hardware

If the connections appear to be correct, either the monitor or the video card is bad. It's also possible the motherboard in the computer is defective, preventing a signal from getting to the video card and monitor. To test what component is bad, either connect a different monitor to your computer or connect your monitor to a different computer. We recommend testing the motherboard for any issues as well.

  • If another monitor works on your computer, the monitor is bad.
  • If your monitor works on another computer, your video card may be having issues. Troubleshoot the video card to determine if it is the cause of the problem.

Tip: If you believe your video card is bad and your computer has onboard video, the motherboard needs to be replaced. You could also install a new video card instead of replacing the motherboard.

Computer not posting

Verify your computer is getting past the POST process and that it is starting up. The "No input signal" message can sometimes appear if the POST process if failing and the computer cannot start up.

If the POST process is failing and the computer is not starting up, it is possible the motherboard could be at fault. A short in the motherboard or a bad capacitor are common causes for a computer motherboard to not pass the POST process.

Monitor works for a while, then loses signal

If the monitor works for a while, then stops working and displays the "No input signal" message, the monitor may be overheating. In the event of overheating, the monitor will stop working to try and prevent further damage.

Fixing a monitor that is overheating is generally not worthwhile. The cost to fix it will likely be more than the cost of buying a new monitor. For that reason, we recommend replacing an overheating monitor.