I've had this problem with my XPS 630 for years and it has to be a hardware issue because I've tried turning the computer on/off, completely reformatting, and installing different operating systems... Nothing seems to fix the problem.
I usually leave my PC playing videos throughout the night, and a lot of times I'll wake up to find the computer is frozen. Then sometimes while just working throughout the day, the computer will start making a weird lagging sound. The lag sound become more obvious when audio/video is playing and will eventually just completely freeze after a while.
What's worse is that restarting the computer sometimes doesn't instantly fix the problem and when it comes back on, it still freezes every few seconds and then comes back. It's like the computer strokes out and needs a few days of me turning the computer on/off for it to stop freezing and fully recover from its hard fail.
Has anybody else experiencing this problem? This YouTube user has the exact same problem with the weird noise: http://www.youtube.com/watch?v=XSwPtJkK4XM
I just upgraded my video card from the GeForce 9800GT that came from Dell (the other one I used for SLI broke) to a GTX 750i and haven't had the issue... yet. But I'm sure it will happen eventually.
I'm looking to upgrade the PC with a new CPU and mobo, but I'm scared to spend a lot on new parts if the problem still occurs afterwards. Maybe the new CPU/mobo is just what it needs, but I was wondering if anybody else might have a better idea of exactly what's happening.