Well, I finally managed to get my nVidia card working properly under Linux again.
I’ve tried this repeatedly with various distrobutions of Linux using the 2.6.x kernel, and following instructions from various sites, but it’s always failed for some reason or another.
Anyway, I finally found out it was because I had disabled “plug’n'play OS” in my motherboard BIOS. Someone had mentioned to me that Linux didn’t need this setting, and that I should turn it off to avoid IRQ issues. Well, evidently my vid card *does* need this to be enabled. This leads me to the suspicion that several other attempts would have worked, and that I’ve been playing the distro round-robin for a couple of months for nothing.
However, I think it was all worth it in the long run. I’m now running Fedora Core 2, and I can play UT2004 again, so I’m a very happy camper indeed.