Hi,
Many of you have been reporting audio issues with our videos (streaming into the SL player). With the help of Niners and the data they've provided to us (thank you!!!) we have isolated this problem to XPSP3 with Silverlight 3. Also, it looks like it's a bug in our encoding process, which Duncan has indentified and fixed. Now, we need your help testing his fix.
If you are running XP with SL3 please test this C9 post and let us know if you hear sound 
http://channel9.msdn.com/posts/Duncanma/Testing-the-Audio-issue-with-XP/
Thank you, Duncan!!!!
C