XP Crashing

I have been running Windows XP Home for about 14 months with no problems until the day before yesterday.It started when my machine crahed to a Blue Fatal Error screen that told me to reboot.I did and got a message saying my machine had recovered from a serious error.After going online again for about 10 mins my machine suddenly rebooted.Again it told me it had recovered from a serious error.After that it was OK fro about 24 hours then it just froze and I could do nothing but reset it.I did not get any messages this time.This happened a few times last night and I noticed a barely audible buzz sound followed by a barely audible whirring sound and then my machine just froze up and I would have to reset again.
I ran an in depth AdAware 6 scan and it found 14 files that I deleted,I also defraged my drive and ran chkdsk,Chkdsk repaired some file(it's name was just a number).
Since then my PC has not crashed but I have still been hearing that quiet buzz followed by the quiet whirring noise every so often but my machine has not froze up again.The last time these noises occured the buzz went about 8 times but I did not get enough time to try and pinpoint it.It was again followed by the whirring sound(which sounds like the noise the hard drive makes just as it is booting).My machine has not frozen again though.
Does anyone have any idea what the hell is happening?

 

Right click My Computer>manage and check out the event viewer. See if anything stands out about the time of these occurances.

Kinda sounds to me that something may be accessing your drive? Is firewall enabled? Try some online virus scanners.

 

Could that buzz you're hearing possibly be a warning sound of some sort? Possibly temp or something similar? I'd have a look at the fans and make sure they're all running properly. Maybe run it with the case open and a fan blowing on it for a day or two and see if you have any problems. From the symptoms you describe it's a possibility anyway.

 

About 15 minutes after my first post in this thread my computer crashed completely.The good thing was I finally knew which part of the PC was causing it.It was the hard drive.Thankfully I had backed up my system about 2 months ago so when I put the new Hard Drive in today I did not have to bugger about installing drivers.It's working OK just now but I'll probably be paranoid for about a fortnight,jumping at every little noise.