Windows 7: PC Freezing

Hello everyone,



Before I start describing my problem I just wanted to say that I used the "search" function bug got lazy and impatient in the process of going through all the threads.

My computer freezes!!

How: I turn on PC, browse around for a few, VGA fan goes crazy and everything freezes immediately. After a couple seconds it goes all 1 unique color, black, grey, brown, it just turns into 1 particular color with too much brightness. All I can do is reboot.

When: After I turn on my PC.

How do I overcome it: I don't, after several reboots I can just get lucky and it won't happen again. That's why I barely restart my PC, I leave it on most of the time.

I don't think it could be overheating but maybe some particular issue with my Windows 7, can't pretty much make a guess there..

Anyway, I'd be greatly appreciative if anyone could help me out on this one.
If I had the funds I would just buy another PC, I love computers and mine is getting a bit old, although my VGA is ATi Sapphire 4850 HD, the motherboard is a bit noobish.. If you need details on my hardware just ask me..

Thank you in advance.

You can test your temps with Speedfan. It sounds like an issue with your video card. Do you get any dump files?