Constant crashing, becoming unbootable, & wiping out files problem.

[Mr_Wobble]

This has stumped me. I've been looking for help on the net, but haven't found anything that quite describes the problem I'm suffering from with my computer.

About three months ago I became fed up of the lack of hard drive space on my PC. So invested in a couple of big 160 GB drives.
Cloning the install of Win2K from the old main drive didn't' work, it just crashed. That was an install that'd been stable, and was about 18 months old (a long time for an install when it comes to Windoze). So I did a fresh install of Win2K.

It was fine for a while. Then a month ago I started having the odd random crash. The Win2K disk utility CHKDSK would automatically run. It would identify some problems, not so much with the main drive, but the secondary drive (which I'm always accessing due to downloads, videos, and MP3's being stored on there. CHKDSK always seems to find "orphaned files", corrects them, which seems to basically involve deleting them. :(
Eventually a crash causes some glitch on the main drive, and it deletes some important files, thus making the system unbootable.

There have been some errors (SYSTEMced & Process1) that according to some sites online, including Microsoft's, don't offer enough help with. They just say run the repair utility. They say it's either registry corruption, or a hardware problem. Not very helpful.

I've recovered the system umpteen times from a Ghost'ed (Ghost is a hard drive backup utility) backup made when all was well, but it always ends up crashing after a while again. I've tried using both drives as the main drive, and still have the same problems.

The thing is, if I put the old hard drive back in as the main drive, it runs perfectly! No problems, no flaws, no crashes. It doesn't matter which of the new drives is the second hard drive, it's completely stable. That makes me doubt it being a hard drive problem.

I can only think of a few things that would cause the problems I've been having....
Windows is crap
A gradual hard drive failure (hard to believe both would go so soon though).
Heat affecting the drives, or system, now the weather is warmer. A possibility as the drives are in acoustic housings, but they're within operating limits.
Faulty IDE cable/s, but that's hard to believe as they haven't been disturbed for some time.
Faulty memory (can cause some glitches in any system).
Some other flaw in the system, such as a loose card, component, lead/cable.

Any ideas at all? Anybody suffered a similar problem?

[Mist]

Not really no. It sounds like the drive is faulty though. Tried the manufacturer's diagnosis? If it's a big brand, then just send it off for replacement/repair.

How's your power supply? Big enough?

[Mr_Wobble]

400 Watt Power supply, made by Zalman. A quality power supply.

The thing with the hard drive fault theory is that it's hard to believe that both new drives have delveloped the same fault at the same time. I've tried running them on their own (ie disconnecting one of them at a time), and the problem still happens. If it were one drive, then as soon as it's disconnected, then the system should become stable again, but that's not happening. :(
I wish I had my spare PC here so I could test every component on a fully working system, one component at a time. :(
My first thought was a possible hard drive failure, but it just doesn't seem to be that now. There's no real way of testing the drives without using another computer, which I don't have to hand.

I'm going to pull every damned component out of that case and totally rebuild it. It needs a tidy up and dusting out in there anyway. It's probably some stupid random thing like a loose plug, cable, lead, or component, somewhere that's causing the drive crashes.