Hello, My computer has run for a long time with out any problems (about a year since upgrading) but about 2 months ago it started shutting off by it's self, everything is running cool(nothing ever gets over 70C)I have even put a better heat sink on my 7950 and fresh past to my cpu heat sink, after reading many forms I reached the conclusion that it must be my psu so I replaced it(500w) but that didn't help I have also used memtest on my ram and 0 errors were detected(I also tested them in different slots), after it turns off I have to weight about 15 seconds before I can turn it back on, the only clue I have to go on is the shut down occurs when I close an application such as photoshop or a game that uses more then 1.2gigs of physical memory it also happened when I closed memtest after it completed scanning and I closed memtest and it shut down. If this problem is solved in another post I would settle for a link, I've just been trying to fix it on my own for a few weeks and have not found the answer on this or other forms.

After reformating, updating all the drivers i could think of flashing the bios and chipset, repairing the registry, testing my ram 4 different ways, some one suggested checking the multiplier on my cpu it was at 15 they said make it 10 i did, now i can run anything without restarting .... it wasn't getting hot so i don't really know of that was the true problem but hey it work