Joe, I just installed an Audigy from one of my older PCs - no more crashes.
It's not a hoodlum problem, but a Rockstar bug. They detect the AC97 as a SB EAX card. Happens with the original CD.
Anyway, the AC 97 worked fine with 95% of games. I'll keep the Audigy, though, for the remaining 5%
Thanks for the help!