Sound Problem in CS:S

When i play source my sound card often locks up or freezes. The sound card is a Creative X-fi XtremeMusic. It used to work fine but i recently reformatted. I have the latest drivers for my mobo, vid card, and sound card, as well as the latest dx. I looked at the steam support forums but they werent much help. Any suggestions?

Have you tried using previous versions of the sound drivers?

I have the same problem with DOD source. Sometimes it locks up with a looping sound. Sometimes the game will actually crash. Sometimes I have to manually restart the computer to get out of it. I had this problem with my old computer about 3 weeks ago and now I have it with a completely brand new system. Updated drivers, tried all the suggestions about hardware acceleration etc... still happens. No idea how to fix it.