Monitor: Going to Sleep + No VGA input ??

Not sure what's going on but my friends' monitor (HP) with the Pavillion desktop pc hasn't been a problem until now. Suddenly the monitor simply will not stay on. Keeps showing "Going to Sleep" message and the error message no VGA input flashes. I've tried rebooting, and checking cables. Any chance it is a bad cable going from the monitor into the pc??? This is a fairly young system with little use.

Thanks very much for any suggestions.

 

Does the monitor come on when you boot?

Has it ever worked?

Can you try booting using onboard (presuming you have a gpu)?

 

When it boots the light comes on to show there is power going to the monitoring, then just a brief message on the screen sayin no VGA input, then shows it is going to sleep mode. No other images on screen. It has always worked great until just recently

Not sure if there is a discrete GPU

 

It could be the power supply. Not enough juice left to power on the monitor.
It could be the cable. Easiest way to check, swap cables and try that.
It could be the monitor. Try another monitor.
It could be the video chip/card. Install another video card.

I usually try the cheapest route first which would be swapping monitors and swapping cables and even putting the monitor power plug into a different outlet.