The sound folder, by default, has only that one file in it. That foler is for custom sounds. Game sounds are all in the "sounds.res" file in the games root installation directory.
Are you using a USB headset, or some other sound device not connected to the system sound card? If you have multiple sound devices, you need to check Windows default sound playback device and make sure it is the correct one. We do not control the default playback device. Other applications will do it for you though, which leads to issues like this.
Aside from that, a DXDIAG output would be helpful.
