It could be a number of problems, If u are talking about it booting up and a blue screen flash, then u should write down the number, a example is STOP:0x0000007E. Try going to safe mode, i think it was F6( if not try all the F buttons), just put it numberous of times untill u see a black screen for u to choose something. then choose safe mode. Also since the blue screen flashes so quickly it is hard to see, it goes away so quickly is becuase MS made it like that in SP2. You can disable it through a option pushing the F6 button.
