Monitor will not boot up is reading no input signal

So either the computer isn't generating a video signal, the cable isn't carrying the signal to the monitor, or else the monitor isn't capable of receiving a video signal.To test this, first try a video cable that you know is good, in case your cable is bad, If it works with the other cable, the problem was your original video cable. If it still doesn't work, put your original cable back, and hook another computer up to the monitor. If the monitor makes the same message, the problem is with the monitor. If the other computer works when connected to this monitor, your problem was that the original computer isn't booting (which could be due to several reasons I will list below), or the video adapter is broken.Possible reasons for the computer not booting: bad power supply, bad power button, bad hard drive, bad memory, bad motherboard component. If you determine that it isn't booting, unplug everything except the keyboard mouse monitor and power cord, to see if that makes a difference. If it boots after that, something you unplugged was causing the problem, plug them each back in one by one, rebooting in between, and when it stops booting properly, the last thing you plugged in is causing the problem.