What sound card are you using? To find out, right click the volume indicator in Windows, select playback devices and see tell us what your default is (Marked with a green checkmark).
Also, does other games with sound work for you? Such as Scogger HD?
Also, does other games with sound work for you? Such as Scogger HD?
Asus N55SF, i7-2670QM (~2,8 ghz under typical load), GeForce GT 555M (only OpenGL)