DVD Playback puzzle

ok, here's a weird one. Help would be welcome, i'm stumped. Friend's got a computer, has a DVD-ROM drive. It'll run programs from disc (say installing a game) fine, EXCEPT for audio/video stuff. DVD playback is garbled, as are any other a/v files. Here's where it gets odd though. An AVI file on the PC itself, runs fine. Burned to a DVD, garbled sound. Burned to a CD, tested in the other CD drive, runs fine.

So it's gotta be the drive itself, right? We've already tried reinstalling all codecs and that jazz just to be safe.. but my understand was that DVD drives don't really have particular drivers, they're all more or less the windows defaults, right? She tells me it's been garbled since day one, so i'm wondering if perhaps the drive itself isn't faulty, but why then would it read OTHER types of files correctly?

Help would be appreciated, i'm stumped on this one.

Alright, I'll give that a shot.. thanks for the 2nd opinion.