I've had similar issues, not totally resolved but... Is your hardrive getting "full" ? Need to make some space or defragg ? Have you checked for updated drivers for your sound card ?

I started having problems when I upgraded to XP. The sound using Music Match Jukebox was horrible. After XP, my system dumped the Turtle Beach soundcard drivers and reverted to Aureal which I presume is an Uncle Billy proggie. Apparently there are no driver updates for the Turtle Beach that will work with XP. I dumped MMJB which is a shame since I purchased lifetime upgrades. Seems to be stable now but for how long ?