The most common cause of this error is a loose cable. Reattach the cable running from your monitor to your PC. If the monitor is still not displaying a signal after firmly reattaching the cable, the problem could lie with the cable, especially if the cable has visible damage.
Why does my computer monitor say no input signal?
A no signal error on a monitor could be a sign that your PC monitor is ignoring the graphics output from your PC. This can sometimes happen if the input source on your monitor is set to the wrong device. Most display monitors have multiple input sources available, including VGA, HDMI, and DVI inputs.
What does it mean input signal not found?
This error message means the input signal from a connected device is not being detected or the correct input is not selected.