I've verified that this happens consistantly. Running Win2K guest under beta4 on a mac mini core duo. Win2K has all current service packs loaded, and parallels tools also loaded. Sound is fine initially. However, if I leave winamp playing a stream, sound will simply stop after approximately 43 minutes of playing. From that point, there will be no sound, and any windows app that attempts to play a sound will either freeze or run as if there were no sound device. Rebooting the guest os brings sound back. If I don't use sound, the guest can run for a day and sound will still be available. It only fails after 43 minutes of continuous playback.
I'm still thinking that sound is not completely stable in Win2K even with the Beta 4 update. I had a kernel panic the other night while booting Win2K right when the intro sound came on. On another occassion, Windows became unstable and sound output quit within Windows until I rebooted the VM. I then decided to disable sound entirely within the VM and it's been smooth sailing now ever since.
