I have the same problem. At work I recently got a brand new computer, a Dell Optiplex 760 with Intel Core2 Duo and Windows Xp. It is nice and fast, but the only problem is that whenever I try to play music, whether it is on Pandora.com or a YouTube type thing from the web, or on WMP whether it is a CD or a saved/ripped file, it does that hiccup thing and it is very annoying. Sometimes it goes for a long time without a problem, but it always recurs.
I tried using the sound troubleshooter and I installed a new driver that was digitally signed by Microsoft, but that did not do it.
What can we do?