Random computer shutdown.

So once I installed W7 beta I was just going around and installing all the programs I needed, when a strange error occurred while I was trying to install AVG, this error didn't give me a message, a warning or anything, but in the middle of the installation my computer just shut off. While confused as to why I was looking at a blank screen all of a sudden, I restarted my computer, windows 7 booted, I sent an error report, and everything seemed to be working fine, until five minutes later when it happened again, and this happened to me every few minutes of use. So I got fed up and decided to just go back into my xp partition, but while xp was loading, it happened again. So I could no longer access my xp partition because my computer just spontaneously shuts off every time. I restored until a time before I got the error and everything seemed fine again for some time, W7 wouldn't shut of randomly and I could go into xp. So about 20 minutes later, while I was installing TF2, it happened again, and I couldn't get into xp again. So I did what I did before and recovered, but this time, I can go into W7 without random shut down, but not into my my xp partition. This is a real big pain in the ass and I would apprieciate any ideas on how to fix this. I'm about to just reintstall windows 7 and see what happens.

If it happens in your XP installation as well, it seems to rule out a software error. It could just be a co-incidence that Windows 7 was a recent addition at the time. I guess you are dual booting?

Also, as there was no error message or blue screen it seems to indicate a deeper fault. You could turn off automatic restart in XP just in case it is a software crash:

http://pcsupport.about.com/od/tipstr...utorestart.htm

Overheating would cause very similar symptoms to those you describe. It might be worth giving your PC a clean and running some temp monitoring software to see if your CPU is too hot.

Your hard drive may be having issues. Most likely when you installed W7, it resized your XP partition, relocating it onto bad sectors, which would then cause some similar errors. It could also be memory, motherboard, or like Ian said, overheating. The W7 disc comes with some memory testing SW, you may want to try running that as well. If that comes back clean you may want to try downloading Hiren's Boot CD and running Hard Drive Regenerator. It's a good tool for detecting and fixing bad sectors on a HDD. If you indeed have bad sectors I would recommend backing up data and purchasing a new HDD. If it's clean you may have some other issues altogether.

If you are comfortable doing so, pop open your case and blow out any dust inside (canned air or air compressors are nice for this). Specifically blow out the heatsink for the CPU and Video card.

I've got also that problem twice in the 64 bit version, not on 32 bit. clicking on an icon, the computer switches off, blank screen. On rebooting I checked the HW monitor all temps. are fine. I'm switching the HDD so one for my Vista 32 one for W7 32 and one HDD for W7 64. The MB ist Intel and the HW monitor works on Vista but not on any W7.