Serious Problem

[Whacker]

OK so there's a number of things we need to look at this point.

First off, something that we might start with is getting you to install Speedfan. When you open it up, there's a tab called S.M.A.R.T., open that up, and select your HDD from the dropdown list. Take a screenshot and post that.

Second, and I'm getting the sneaking suspicion that this might be the real culprit, is your ATA controller on your mobo might be going south. There really isn't any way to test this aside from swapping out with a new known good mobo and running for some time to check for stability.

Third, there's a potential it could be other components. RAM and PSU are often tricky to troubleshoot and can create problems that are hard to trace back to them. Heat is another problem, unless you're 100% sure of the ranges of temps that your equipment is experiencing then it's not wise to eliminate that, that's not something one can get from "feel" or "intuition."

Start with that and we'll work from there.

[Evil_Maniac From Mars]

1) I left it overnight, and it started up fine, albiet with a little bit of lag. I still want to know what's wrong though. My computer seems to have an annoying (but handy) feature of fixing itself without ever telling me what went wrong.
2) Temperature according to nVidia MonitorView is 36 Celsius for the CPU, 27 for the system, and 53 for the GPU. This is right now upon startup, though from experience those won't rise too much.
3) According to SpeedFan, HD is at 27C.
4)

Spoiler Alert, click show to read: 

And sorry about the spraypaint effect in there.

[Caius]

53 for the GPU

This temperature isn't too good. When did you run it? (When you started the pc, played a game, after some hours of use...?)

[Evil_Maniac From Mars]

This temperature isn't too good. When did you run it? (When you started the pc, played a game, after some hours of use...?)

The card is a superclocked 8800GTS, and it never artifacts or anything. nVidia GPUs are apparently rated past 120C, and 70+ is the mark where cooling should be increased. I've never hit 70 yet.

According to nVidia forums.

[Whacker]

This temperature isn't too good. When did you run it? (When you started the pc, played a game, after some hours of use...?)

Actually Caius.... that temp is fine. My GPU idles at 65C usually. The throttleback point for most modern cards is in the area of 100C, so they're designed to operate up there in those goatcooking temps.

EMFM, your HDD appears to be rather healthy. Seagate had some problems with a number of drives made in China by the former Maxtor assembly plants. (Maxtor sucks the big one)

At this point, you might try a new HDD cable. Try switching HDD ATA/SATA ports on your mobo. Try powering your HDD from a different cable coming out of the PSU, try a different rail if possible. If that doesn't work, then my guess would be it's one of either the mobo (most likely), RAM (less likely), or PSU (big stretch). If you've done a low level format after a partition wipe, and then a fresh basic XP reinstall (retail, not OEM) then I highly doubt your problems are software related.

[Evil_Maniac From Mars]

EMFM, your HDD appears to be rather healthy. Seagate had some problems with a number of drives made in China by the former Maxtor assembly plants. (Maxtor sucks the big one)

I already had to send one drive back to Seagate, and the one I have in here is the replacement. This one isn't doing anything overtly abnormal though, the last one I sent in was chugging loudly.

At this point, you might try a new HDD cable. Try switching HDD ATA/SATA ports on your mobo. Try powering your HDD from a different cable coming out of the PSU, try a different rail if possible. If that doesn't work, then my guess would be it's one of either the mobo (most likely), RAM (less likely), or PSU (big stretch). If you've done a low level format after a partition wipe, and then a fresh basic XP reinstall (retail, not OEM) then I highly doubt your problems are software related.

Alright, I'll take a look around inside the case. Thanks.