Since a week or two my computer seems to freeze randomly, especially when I've just turned it on. Windows' interfaces are the first to stop responding, then after a few seconds the mouse freezes. Strangely, running processes, such as audio or video, keep playing (although staggering). The computer doesn't respond to any commands, and I have to reboot it manually...

Does anyone have an idea what could cause this behavior? It doesn't seem like a software-issue to me? The PC is about two years old, a dual-core which has lately been checked when the harddisk broke.

I'd appreciate any help. Thanks.