I'll be forever thankful if someone can shed some light on my current computer problems and how to go about fixing them.

Problem 1: For about a week or two now, if the a/c isn't running (so it seems) my computer will just randomly reboot. I was just chalking this up to overheating issues, but I've never had this issue before. I do need to do a cleaning on the insides of the computer, it hasn't been done in about a year....but still, this is the first my computer has ever just randomly rebooted on a consistent basis.

Problem 2: Aside from the reboot problem, my computer installed some windows updates the other day - one of which was service pack 3. After the mandatory restart the moment it would get to where windows should start loading, it would reboot again. Was an ongoing cycle (get to windows, reboot, etc) - once in awhile it would stop and show the options page to 'start windows normally" "safe mode" "last known good configuration". None of which worked. The only way i got my computer to boot up normally was by doing f8 before windows was to load, select HDD for start up and then it would run.

It's only given me the 2nd problem ever since installing service pack 3 - is that the culprit of my 2nd problem?

Anyone with a suggestion on how to fix problems 1 and 2? I'd like to nip this before it gets to the point my hard drive totally explodes and i have to go buy a bunch of new shit.

Thanks for any input and advice.

Also, in case it's needed and of some importance

OS is Windows XP
AMD athlon 64 fx
2.8GHZ
2GB ram

If by some chance something else is needed to know, let me know. That's just off the top of my head as i built this computer maybe 2 years ago.