PC locks up after loading XP and monitor shuts off

[gssstuff]

I am trying to fix a friends computer. For some reason, the PC will
just lock up. It is usally after windows has loaded, but not always.
About 1/3 of the time, it will lock up with the display being frozen.
The other 2/3 of the time, it will lock up and the monitor will shut
off.

Unfortunately, he did not appreciate the need for anti-virus or
firewall protection when using broadband connection. I ran a virus
scan and cleared out nearly 80 viruses and trojan horses from the
computer (it was kind of reassuring in that it proves the av stuff
works!). I tried booting it after clearing the mess out and it did not
help. I tried reloading XP cuz I assume there may be some corruption.
It locks up too. I can get the computer to boot and be somewhat stable
in safe mode, but when I try to mess with any of the system settings,
it then crashes out.

Does this sound like an OS problem, or a hardware problem? Are there
any system level diagnostic tools that I should run on it.

My gut tells me that it is time to redo the whole mess, but I don't
want to waste my time if it is a hardware issue.

Any guidance is appreciated!

 

[Jerry]

Did you verify whether or not the monitor and/or video card are or are not
going bad by swapping them out with a known good unit?

 

[gssstuff]

I have used the monitor on another PC without issue. Cannot swap out
the vc as it is an integrated chipset on the motherboard. Hence, why I
was looking for some diagnostics.

 

[gssstuff]

the saga continues....

OK, I have swapped out vc between two PCs, vc from bad pc works fine in
good pc. vc from good does not allow bad pc to boot, even after
messing with bios.

Have run memtest for 24 hours and got no errors... I did it twice, once
in one memory slot, once in another.

Have wiped hard drive in attempt to reinstall windows. The PC works
great in dos mode. When installing windows, I got a BSOD...

STOP: 0x0000008E (0xc0000005, 0xbf8154a, 0xf86e5c04,0x00000000)
win32k.sys - address bf81e54a base at bf8500000, datestamp 41107f7a
Beginning dump of physical memory

After this, I rebooted to see if it was an anomoly. Reran windows
install, attempted to Repair. It starts repairing and then the monitor
shuts off but system fans and drives are still active.

any thoughts anyone?