I've just built a new system and am experiencing a weird hard-freezing issue. The system will randomly lock up completely for no obvious reason (does so whilst idle or loaded). With a GTX 460 card in, the display goes completely blank and the monitor goes into standby. When I press reset, the motherboard sounds the "no VGA" beeps. Normally it comes back after a cold reboot, but on one occassion I had to leave it an hour or so before it would come back. When I tried with a friend's GT 260, the freezes still occur, but the screen remains on, so that rules out the graphics card. The system comes back fine with that card in after pressing reset. Motherboard: Asus P8P67 (B3 revision) CPU: Intel i7-2600 RAM: G.Skill RipJawsX 2x4GB 1600MHz (F3-12800CL9D-8GBXL - not listed in Asus' s QVL, but G.Skill state it's compatible) PSU: Coolermaster Silent Pro Modular 700W It doesn't seem to be heat-related (CPU core temp. ~60 degrees whilst gaming, motherboard temp ~34 degrees and graphics card ~60 degrees). However, I am just wondering if it may be related to the thermal paste. The CPU temperature hit 90 degrees whilst running Prime95, which does worry me slightly, despite that being within the stated limits. I'm running it now with one stick of RAM removed (same issue occurred with the other stick removed) to see if that makes any difference, although memtest86+ and Windows Memory Diagnostic both came up clear (edit: no luck with the other stick). To be honest, I'm completely stumped. Does anyone have any suggestions?