Windows 7 Sound lockups in media center

Hi all...first post here...great site BTW.

ok...My problem is this: When I go to watch tv using Media center...all goes well...but after a bit...the sound will go crazy..meaining it will get all garbled, and then eventually stop working.I am using a creative Audigy 2z 5.1 the sound works fine with all other applications...can anyone enlighten me?

System specs
Cpu=q9450
8.0gigs 8500 gskill ram
evga 780i mobo
Sata hdd
triple boot Xp/Vista Ultimate 64/Windows 7 64

Thank you in Advance.