Hey guys... After a few hours of usage, my pc freezes, and I have to reboot it. First the applications stop responding, about 10 seconds later the keyboard stops responding(Num lock stays on despite me hitting the key). About 10 seconds after that, the mouse stops moving. During all this, my HDD seems to be a bit busy, blinking a few times a second. But about 5-10 seconds after that, even the HDD goes quiet. And the PC sits, idle & totally frozen. Now Im thinking its one of two things causing this: (1) A hardware fault. (2) A virus, worm, etc.... My Power Supply has been troubling me for a few months now. It makes a loud whirring sound every now & then, at seemingly random times. Could this cause the system to become unstable & freeze? Alternatively, could it be the 2nd option? Could something software related have this kind of effect? I have very limited net access on this PC, which I basically use to keep my AVG up to date. The one thing that can predictably cause it to freeze is VirtualPC. If I've been doing anything, and start up VPC, it'll freeze within a few minutes. To use VPC, I gotta reboot, and then use it. Any help & ideas is highly appreciated.