Did you seen if isn't nothing on CF settings?
Sound works on another applications/games? Depending of your answer, try reinstalling your audio driver.
Sound working at all applications. But don't working at Crossfire or Crossfire don't want use it. :-DDDDD
I would recommend you use the Z8Games Technical Support, they surely must know more than us, except if someone already had this problem before.
uninstalll realtik iv experinced it
ahh...this problem...had the same thing. Do u use speakers?
check ur speakers, make sure they are alright