have problems with XP, please help

[snort]

First off, this isn't my computer, its one I built for a friend of my gfs. Also, I don't have access to it right off, my gf has to wander over there and try the various suggestions.

Secondly, heres the hardware config:
MSI K7TPro2 (not the -RU)
Athlon XP 1600+
512MB Crucial PC2100
40gb IBM deskstar (I didn't realize problems with them were so bad until AFTER I ordered it)
Radeon 7500 Retail
3Com PCI Modem Pro (real modem)
Alpha PAL8045 w/Delta Fan
Liteon 16x CDR
Liteon DVD-ROM
using the mb's built in sound
PSU is a 300 watt unit that came with the case

Third, this is what its doing:

On startup, sometimes XP will give a "serious error" message - but not always. Aparently the message is always the same, but the info provides no useful (to me) clues. BPCode: something, etc.

Occasionally, connecting to the net, it'll go through a crash/reboot cycle. This seems to happen more often when the computer has just been turned on, less so when its been on for a few hours.

Mem settings as follows. CAS latency at 2.5, precharge time at 3T, RAS pulse at 6T, RAS to CAS at 3T, 4-way interleave, and a burst length of 4QW.

AGP mode _IS_ 4x, 64mb aperture, Fast writes disabled, write disabled, read disabled, synch disabled.

XP has been upgraded with all of the hot fixes, all the latest stable drivers have been installed (VIA's and ATI's).

I'm all out of ideas here. I have this weird feeling its hardware, but I'm not sure. Its a totally fresh install, and I used this article (http://cweb.msi.com.tw/eforum/?target=article&tid=1769) for the baseline bios settings.

I really don't think its the PSU, as there are no problems under load. The cpu temps are all ok.

I'm just really confused and ready to tell her to put win2k on it instead.

[Yodums]

Overclocked?

Check the rails of the PSU under load.

Try disabling all the unecessaries thing at startup(eg; Microsoft Office), it could be something that he installed which is starting up at the startup and the program is a bad executable and its crashing the system.

Ask he did before this happened, could be useful information to conclude this problem.

Yodums

[snort]

not overclocked at all. I tried it initally, just to see if it would. Got it to about 1530, but without unlocking the cpu I couldn't go farther.

But I set it back to default before turning the box over to her.

The only thing running is MSI's temp sensing utility (can't remember what its called).

I'll have my gf wander over there soon, and switch all that stuff off.

[takiwa]

Did you install the OS while the cpu was o/c'ed? If you did, you may need a fresh install...

Also, I've found out (several times) that, unless you are having problems that are within the definitions of the hotfix or update...DO NOT download them. They can (sometimes) make things worse...

Lastly, have you checked the breakers in his house? Seriously...until I changed the breaker in my box (from a 20 to a 40), I was randomly rebooting, whenever someone turned on a light! It's kinda funny, now that I think about it...hehe

About what Yodems suggested...does it reboot and crash with a fresh install with NO programs installed? It may be a third-party software thing...you may have to run some progs in compatibility for XP...

Just some random thoughts, dude