About two weeks ago I started to get random system freezing/crashing. Checked inside the case to find that the fan on the Power Supply wasn't spinning. Even with the fan not spinning I still got some decent on time without crashing (sometimes over 3 hours because of the cool area). Replaced the Power supply and got about 45 minutes of on time before I started rebooting again. Checked all my plugs and the temperature on my BIOs and everything seemed fine. Tryed to get it going again today once I got home from school, (left the computer on this morning, came back and the XP professional screen saver was on, leading me to believe it had rebooted after I left and froze at the login screen). Checked the plugs again and after a few pitiful rebooting attempts, managed to get into my account for a few minutes. System rebooted again... This is when things started getting wierd. I tried searching for a better virus scanning software than one of my old McAfee I am currently using while in Safe Mode with Networking and after trying to install Windows Live One Care, my system rebooted again. Booted up into Safe Mode with Networking again and it rebooted right when I opened Internet Explorer (Can't instal WLOC in FireFox). Went into safe mode and deleted some suspicious files--Rebooted again right after I emptied the recylce bin. Logged back into safe mode and disabled the system failure restart, then started a Virus scan with McAfee. Left the room for abit and came back 5 minutes later with my computer frozen at the loading screen (apaprently it rebooted again while I was away). From what I can tell, if this is a virus, then it dosn't require internet access, because sometimes I crash at the screen where it loads all my motherboard and hardware stats. And then there's the times where it seems to coincedently crash at times where I'm searching for viruses or removing suspicious files. Another note: The power supply I replaced with my malfunctioning one was from another computer. When that didn't work I removed the fan from the working PS, and put it in my previously working PS. Same problem. From what I've been able to find, i've come to the conclusion that this is either a very aggresive virus or a Motherboard/Power supply error. I have already ordered a new tower with a new power supply but some more help would be nice. Thanks.