This sounds like a cache problem, which can happen over time.   To fix tthis issue: clear the prefetch folder cache boot up in safemode -> windowskey -> select run type in prefetch click ok and when the screen comes up with a list delete all of them You should clear out your prefetch anyways every month or two.
i have a dell studio xps m1340 run win7 ultimat and run into a trouble recently. when i star my computer it gets to window logo and keeps flashing. i cant get to the desktop. when i run it under safe mode trouble shooting report superfetch not working. i dont know how to correct the problem and  i can re-install window neither.
superfetch not working