Monitor problem

Disconnect the cable from the computer and see if you have the same problem. If you don't and you get a no signal present message the problem is related to your cable's connection to the display adapter connector or your display adapter itself.

I can assist you further if you get the expected message above after disconnecting the cable.

If it does the same thing after disconnecting the cable the monitor is no longer any good and has failed. There is nothing you can do to fix this problem other than to take it to a qualified repair shop that will work on monitors or you could have it replaced under warranty if one exists.

Hope this has fixed ya.
Regards,
Worldvet