Previews pause after 2-3 seconds in Music Store

When I try to play a 30 second clip from the music store it pauses after about 2 seconds. I can hit play again and it will pick up right where it left off (for another 2 seconds). I've uninstalled and reinstalled both iTunes and Quicktime with no luck. Songs from my library play fine. It's just the previews that give me trouble.

Thanks for any help.

Windows XP Pro