Prime 95 will not guarantee stability. How long did you run it? Chances are, you have an unstable o/c. That's why stage 1 stability testing is UT2k3 with full graphics. Stage 2 is watching a DVD while running a number of other programs in the background (DiVx in WMP, WinAmp with visuals, ATI tv, plus monitoring programs). I try to incorporate funner things into o/c'ing, and that generally will crash quickly if there's any problem. Stage 3 is the usual overnight Prime95 either 2 instances or 1 with 3dMark03 looped, I try to avoid the longer term torture testing until I'm convinced I'll stick to an o/c, there is a risk of damaging components if you're doing a lot of switching and running double Prime95 every night.