Sorry for the long post but I wanted to give as much info as possible. I recently built a new system and installed Windows 7 Professional 64 bit. Ever since I built it the system has had a problem where it will freeze at random times. When it freezes the mouse simply stops moving and the computer is completely unresponsive, requiring a hard reboot. The time that the system takes to freeze varies greatly, sometimes only a few minutes, sometimes up to 36 hours. The freezes tend to occur mostly while the system is idle. It seems to be fine during gaming and i've had no freezes whilst playing games for hours at a time. The freezes do not occur when the system is in safe mode. Apart from the freezing the system runs fine. System specs are as follows: - Intel Core i7 2600K - Asus P8P67 Deluxe (B3 Stepping) - G.Skill Ripjaws-X 8GB kit (4GBx2) DDR3 1600 F3-12800CL9D-8GBXL - Asus 6950 2GB VGA card - OCZ Vertex2-E 120GB SSD - 2 x Western Digital 2TB SATA2 HDD (WD20EARS) - Corsair HX-750 PSU - Antec 900 case So far I have tried everything I can think of. Here is a list of what I have tried already with no luck: - Updated all drivers to latest versions - Checked Event Viewer for errors but could only find a Kernal ID-41 power error indicating that the system has rebooted without cleanly shutting down first (I don't really know what to look for here so I may have missed something) - Performed a clean boot with all non-Microsoft services disabled, still crashes - Ran SFC/SCANNOW command, no errors detected - Disabled all display and system sleep options - Reinstalled fresh copies Windows 7 on the SSD (both 64 bit and 32 bit versions, both still froze) - Replaced the motherboard (upgraded to B3 stepping after the Cougar Point recall for the board's SATA controller) - Tested the RAM with Memtest for 10+ hours, no errors - Swapped the video card with the card from from my other computer which is confirmed working, still froze - Reinstalled Windows 7 x64 on a different HDD (and all other drives disconnected), still froze - I also installed my old copy of Windows XP Pro 32 bit on the system and this actually did run without freezing The fact that Windows XP and Windows 7 safe mode run successfully on the system without freezing prompts me to think it's not a hardware problem but I don't know what else to try in Windows 7 to get it run normally without freezing. Any help would be appreciated.