My computer screen was blanking out after a couple of seconds this morning. Any techies out there have any idea what was happening?

Last night everything was fine. Shut the computer off, went to bed. This morning the montior would only stay on for about two seconds, then black out. I don’t have any screen saver options selected, but for lack of any other idea’s I went to the control panel (in fits and starts) reset the screen saver to “none” (even though that’s where it already was.) Well, it took the picture I had set up as my desktop off, and replaced it with an all black background. But, apparently it somehow fixed the problem, or it was just a coincidence. Any idea what’s going on with my computer?