[Omega]

Well, although it seems strange, your Voodoo 3 had one advantage in UT: Glide.  I wouldn't think that a GF2 GTS would have problems running UT, but I suppose it's possible.  What are the specs of the rest of your system?

Possibly there are residual drivers left over from your Voodoo 3, so if you search your computer for 3dfx and delete the files, and your registry for 3dfx and/or Voodoo and do likewise.  Beware, though, when deleting files and registry entries.  It's usually a good idea to back up what you're about to delete if you're not sure if you'll be ok without it.  Reinstalling UT could theoretically help too.

As for the no video signal, I'm kind of baffled.  The only thing I can think of is that something is touching the card's contacts (anywhere that has metal and a signal running through it) and shorting it out.  Make sure everything's clear of it next time if it happens.  I suppose it's also possible that the card just became unseated, so make sure you have it in securely, and the bracket screwed in.

By the way, do you still have your Voodoo 3 3000 PCI?