monitor goes blank while gaming!!!

[Yavin]

I have a problem while playing certain games. when i reach certain areas of certain games my monitor goes blank but the game seems to be still running. I can hear gunshots or dialogues but the monitor seems like turned off but the led of monitor blinks continuously. Then i have no other alternative besides to restart pc pressing winlogokey+U+r. I have this problem in Batman AA,FEAR PM, OFR. even small game like air assault 2. My gfx card is sapphire 4670 512mbddr3,2bg corsair value ram,dual core proc,samsung 17"flat crt,MSI-P6ngm-FD mobo,450w psu.

I disassembled and cleaned all pc parts. formatted and installed xpsp2, updated video card and audio driver to latest, installed latest directx, lowered resolution and settings of games, changed sceen refresh rate. BUT the problem still persists. It occurs when I reach certain areas of a game but sometimes can bypass by going through different route of a game. like I completed OFR by going through different way.

I didn't have this problem in games like Crysis series, wanted, COD4,cod5,GRAW 2,painkiller etc.

Can anyone suggest what i can do?

[Zangetsu]

hmm strange....may be games files r corrupt..this problem is related will video card...
check the video card in other system by playin the same games to dat certain point