Computer locking up -- next step in troubleshooting?

[xboxist]

The symptoms:

My system of 4 years old is finally acting up. Had zero problems previously. About a week ago it would start to give me a hard freeze/lockup after anywhere from 10 minutes to 2 hours after the last reboot. No error messages, no warnings, just boom... no response on any buttons pressed or any icons clicked. The mouse would move freely, but I can't do anything with it because nothing responds to the clicking. Ctrl-Alt-Del doesn't bring up that window. Absolutely zero response from windows of any kind. My only known recourse is to simply do a hard reboot. The Event Viewer doesn't show any errors related to the time of the lock-up, once I reboot. It's like the lockup is so sudden and thorough that nothing has a chance to be written to the log.

The above happens seemingly no matter what I'm doing. It will do it if I'm browsing. It will do it even if I reboot, and let that fresh boot just sit on the desktop. If I walk away from that reboot and come back in 30 minutes, there's a good chance that it will already be locked up again just from sitting there.


My computer:

XP SP3
Core 2 Duo 6600
ATI x1900xt
2GB RAM
No overlocks of any sort. No new hardware added in the past 12 months or so.


What I've done to try to isolate and/or fix it:

-I used Windows update.
-I installed 2 different adware suites and 2 different anti-virus suites and ran full sweeps (nothing found)
-I opened up my case and reseated all hardware, and blew out any dust in case it was a heat issue
-I uninstalled a bunch of non-essential programs (not a lot there to begin with; I don't like program clutter)
-I ran msconfig and told Windows to boot with only essential services


Ideas? I know it could still be a ton of things, but I'm not sure what step to next take. My XP install CD is 200 miles away so I can't reinstall Windows yet. I don't have spare computer laying around to swap RAM, etc. What things should I try next that I can do within the system? THANK YOU!

 

[lxskllr]

Test your ram with Memtest86+
Run chkdsk /r on the hd
Borrow a cd and perform a repair install?

 

[xboxist]

Thanks.

Did two complete passes with Memtest, no errors (will further test overnight)
chkdsk /r returned no errors

Guess I'm trying Windows reinstall next.

 

[Trashman]

I would be curious to know if its software/drivers or hardware problem, what happens to system is you were to boot in safe mode.

 

[xboxist]

Ok, I've been testing this computer all day long. Here's an update on things:

First of all, I installed some software for monitoring CPU, GPU and overall internal case temps. Everything is reading well within expected ranges of temperatures. So while it doesn't necessarily rule out that either of those components are failing, it shouldn't mean that they're failing due to overheating if one of them is indeed going bad.

I tried a couple of previous restore points, well before the lock-ups started to happen. Didn't help.

Lock-ups happened while messing around with stuff in Safe Mode. Soooo... I guess this means there's a chance it's hardware related, right? Memtest says RAM is fine, and my CPU/GPU aren't overheating. So beyond that, I don't really know how/what to test next.

I can reinstall my OS, but I don't have my XP cd here and probably won't be able to get my hands on it until a month or so. So I'm screwed unless you guys have some suggestions for me to try!

 

[lxskllr]

Check for bulging caps on the MB. It could also be the PSU.

 

[xboxist]

I booted into Ubuntu from a CD, and browsed the web for a good 2+ hours. No lock-ups, so I decided that was good enough for me and went ahead and reinstalled XP.

So far it's been fine so I'm hoping that was all that was wrong, and that my hardware is fine.