Chronic crashing PC problem - Please help!

[sansanatomy]

My system, which I custom built around 4 years ago or so:
AMD Athlon XP 1900+
ASUS A7V266 motherboard (almost certain of the model, not positive)
Windows XP Pro
2 IDE HD's 60 GB a piece - Primary IDE
CDR & DVD ROM drives on Secondary IDE
2 Maxtor IDE HD's (about 100 GB a piece) off of Sil 0680 ATA PCI Raid card
Antec PP-403X 400w switching power supply
RAM: GET 512 MB DDR PC266 (also tried another compatible RAM chip, still had crashing problems)
Creative SB Live Platinum soundcard
GeForce MX2 video, 19" monitor
an ethernet card
McAfee virusscan (with updates)

The problem:
For the last few months or so I have been having frequent & reoccuring problems with my computer crashing. The crashes have been exponentially frequent until now when my computer will load XP and within only a few minutes it will either freeze, go to the "blue screen" and reboot right away, or just reboot without warning. Sometimes, as soon as XP finishes the boot, an error window comes up saying "The system has recovered from a serious error." Usually I click "Don't report" and the window goes away, but sometimes it keeps coming up again no matter how many times I close it.
After the computer crashes and reboots itself, it seems to operate at half-speed, with the BIOS startup process & xp running VERY slow. If I power off the computer right away & power on, the computer automatically brings up the BIOS setup stating "During the last boot up, your system hung for an improper CPU setting. Your system is now working is now working in Safe Mode. To optimize the system & performance reliability, make sure the CPU speed conforms to the specifications of your PC."
If instead I power off for 5-10 minutes and power on, the computer boots as normal, at normal speed, but again I have the same crashing problems. When the freezing & crashing problems started happening more & more, I changes the CPU speed in BIOS setup from 1600 MHZ to 1200 Mhz. This stoppped the crashing problem until more recently, when again it started occuring again.
Using the ASUS Probe windows application I have noticed that the processor quickly reaches a temp of 88 degrees soon after booting within a couple minutes. It seems likely that my CPU is shot, but I'm looking for some 2nd opinions. I'm looking for a replacement motherboard/CPU combo that's very affordable but can handle some audio recording and processing software.
Your feedback is much appreciated. Thank you!

[david eaton]

It certainly sounds like an overheating problem. Is the temperature reported in Centigrade or Fahrenheit? If it's centigrade, then its waaay too hot! Check the heatsink/fan for dust, and also check that the fan runs OK

[sansanatomy]

thanks for the reply
its in Farhenheit, i dont think there is a fan/dust problem tho

[Quantax]

That doesn't suggest an overheating CPU.

In the Run dialog box, you could type in "eventvwr", click OK and see what errors are reported when this occurs. You should also have a setting configured(and maybe you already do)in the Device Manager so that there's not an automatic reboot so instead the error message appears and that will provide you with needed info about the possible cause.

[sansanatomy]

there are a lot of "true vector errors" under applications.
where can i get to those device manager options?

i jsut took off the cpu fan and heatsink, they were both caked with dust. i think that's the problem. so far so good anyway.
thanks for your help everyone

PS also i was wrong, those temps were celcius not fahrenheit

[Whyzman]

i jsut took off the cpu fan and heatsink, they were both caked with dust. Yep, definitely a good starting place as mentioned earlier...

I use an inexpensive airconditioning filter that I cut into appropriate pieces and place in front of my case intake fan. Every couple of months I either wash it out or simply replace...