having some video problems

[amdGuy]

hey all, i'm having some problems with my video card, ATI RADEON 9800 PRO(AGP) 128MB. I recently bought Far Cry and installed it the other night. for some reason i can only play it for about 1 minute before my monitor goes black and the power light starts flashing. although i recently found out it now does this with all my games! sometimes i get an error message saying that my video card couldn't execute some graphic commands from the game. Ive tried changing the AGP mode from 8x to 4x and various other settings, even reinstalling the original drivers doesn't seem to work. ne body know what's going on! thanks!!