Crysis gets sound error???

I installed Crysis (not war ahead). I set at medium. But I got a serious problem. The game has no sound. I checked very carefully the ''Sound'' dir and it doesn't empty. In game, I pressed '' ~ '' and see a line said that it didn't reconize my sound system. I updated Sound driver to the latest but the same error happen.I installed the same disk for my pal but he his game has sound and he uses the same sound system like me. WHY? WHY? WHY? I do not understand. Cry engine error?