Monitor Stuck In Power Save Mode

How to take it out of this mode? My friend's PC was left on since last Thursday and when he tried to go n 2day, he got this message.

What can I do to help him?

Hello. Glad to have you here at GeekPolice.

Please wait here, while I refer you to an excellent Tech Advisor or other staff.

Hey, I Got it fixed. I held the power button for like 15 seconds...

Ahh cool. Marked as solved.