Hi, I have a problem over the last few weeks where my computer crashes after approx 3 hours of play on my game, the screen goes black and before the computer reboots automatically, a verbal announcement states on my speakers saying `video fan failed`. the pc guy has checked my ATI Radeon 4800 series graphics card which he installed 6 months ago and he says it is ok. Could there be another prob maybe, thank you for any help.