No Input Signal error message
Tip: This document is for troubleshooting the no input signal message when connecting a monitor to a computer. If this is a laptop see our steps on connecting a monitor to a laptop.
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 data cable will connect to the back of your computer using either a VGA connector or DVI connector usually. In the picture below, is an example of a VGA cable and the connector on the video card.
If the monitor appears to be connected properly, verify that a cable is not loose by disconnecting the cable that goes from your computer to your monitor from the back of the monitor. 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 cables pins are bent by examining the cables end. If any of the cables pins are bent or broken, the cable may be defective.
Next, disconnect the data cable connected to the back of the computer and then reconnect the cable. When connecting the cable in the back of the computer ensure the cable connection is tight. With a VGA style connector, like the one shown earlier this cable has screws that can be tightened to hold the connector in place.
Tip: Some computers may have an 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.
If the connections appear to be correct, either the monitor or the computer video card is bad. To test what component is bad either connect a different monitor to your computer or connect your monitor to a different computer.
- If another monitor works on your computer, the monitor is bad.
- If your monitor works on another computer, your video card is bad. Troubleshoot the bad video card to determine if it is the video card.
Tip: If you believe your video card is bad and your computer has onboard video, the motherboard needs to be replaced.