I have recently been having some trouble with my PC and I think it is due to overheating but i've tried several things and it seemed to help but not solve the problem. I am running a P4 3.0ghz processor with Hyperthreading on an ABIT A17 MB with an I865 Chipset. I also have a SATA HDD and a Sapphire ATI Radeon 9800 pro video card, i'm not sure if those are relevant to the issue but thought i'd make sure. At first i had the side of my case open with a large window fan blowing into it to keep it from overheating (it had a few times) i was in a warm room in a house with no AC but have recently moved it into a basement with AC. When i put the case back together i started it up and right as the windows xp login screen came up it would freeze and restart itself. So i tore the entire computer apart and maticulously cleaned the dust off of each peice of hardware and put the PC back together. It then ran fine for about 5 minutes but would freeze and restart again. So I pulled all of the fans, cleaned them and repositioned them to maximize airflow (4 fans, 1-120mm in the front, 1-80mm on the side and 2-80mm on the back) and again it ran a little longer but eventually the same problem, so now I have also reset the heatsink with new thermal compound and underclocked my processor from 3.0ghz to 2.4ghz. The PC runs fairly well but whenever i try to start up WoW or another process-intensive program it will run for awhile, freeze and restart. I am out of ideas as to how to fix this and was wondering if there are any other reasons to the freezing or restarts or any other fixes i could do to take care of this problem. Is there a chance something was permanently damaged? Please help, thank you.

(the cpu is idling around 45-46c and jumps to around 50-52c once in awhile)

Chances are with temps like that its not overheating (70-80 is overheating IMO).

Id question the RAM tbh, can you give a check with MemTest or similar?
Either that or the gfx card, does yours have a temp monitoring option u could check?

hmm.. i can't find anywhere to monitor the graphics card temp. Although i had suspected that to be the problem, i've heard the radeon 9800's have some issues and it gets extremely hot to the touch at times... I'll try buying an aftermarket fan for it to see if that solves the problem and keep you posted.. thanks for the reply. I doubt it's the ram i've never had any memory errors or problems and it's fairly good quality ram.