Hello, I recently built the following system: Asus m4a785td-m Evo Mobo Phenom II 965 125W 3.4GHz CPU Corsair Dominator 1600mhz 2x2GB RAM Coolermaster M series 600W PSU XFX 5870 1GB GFX 1TB Samsung spinpoint F3 HDD Windows 7 64-bit It worked without a problem for about a week, then started freezing on rare occasions, and gradually they got more and more frequent. Now I can barely do anything which doesn't cause the pc to freeze. It doesn't even give me the courtousy of a BSoD, the image just freezes, and if there was a sound playing at the time it would play a very short (last few ms) sound continuously. Windows event viewer shows nothing helpful, Critical: "The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly." Error: "The previous system shutdown at 17:35:26 on 07/02/2010 was unexpected." I've tried swapping the RAM out for another set of 2X2GB of the same type of ram (Bought two sets of 2x2GB sticks but my aftermarket cpu cooler was too big to fit them all in), updated all drivers, updated bios, reformatted, ran the windows memory test (which came up clean), tried running on onboard graphics (4200) instead of the 5870, but the problem persists. The best way of recreating the freeze is to run the windows experience index test, where it will almost always freeze at "Tuning Windows media decoding" The temperatures are fine, cpu idles at 24-26 degree's, gfx at about the same, and under load the cpu doesn't exceed 40 degree's. Any help would be much appreciated.