Monitor

are you sure that its your screen? try another screen if it does it. if not, then try using a differant res and refresh rate.
beings that your screen freezes and then goes black on exit.
I would say, your game is heating up your computer by useing stuff that usually dont get used. try removing the cover and carefully cleaning all heat sync's so it can breath.
if the problem continues, please report back, with more info, on what game and what model system you have with operating system. also if you added a video card.