But no, it crashed madly under heavy disk load even with the disk hooked up to the regular IDE interface. It would appear that the motherboard is probably just defective, although I'm only figuring it out something like two or three years later.
So I just decided to buy a new motherboard for it. But the Athlon is known for flaky interaction with GeForce, so I figured maybe as long as I was doing that, I should just get a new Intel CPU. And, hey, I might as well get a good CPU too. And I want a decent motherboard--specifically one with lots of PCI slots. But trying to find a good one online, I end up getting one with onboard RAID and USB 2.0 and two Firewire ports, because, hey, might as well build it to last. Oh, and a new CPU means by old SDR RAM needs to be replaced by DDR RAM. 512M of that stuff ain't cheap either.
The Dell machine--1.9Ghz, 256MB DDR, 30G hd, GF2MX--was $800. This new set of parts (momboard, 2Ghz CPU, 512MB DDR) was $500. I probably should have just shelled out for the whole machine. Although really, the motherboard here should be much much better than the one in the Dell... assuming it isn't an unstable piece of expensive crap like the last one was.