Plutonium

So yeah, when i play BO2 i don't have the ingame sound, i don't know why. I have the sound with MW3 and other games but not with bo2 i tried everything with the sound and reinstalled the game but still can't fix.. i can only hear ppl talking on voice chat but not the game sound itself, so yeah i play without sound and it's kinda annoying (btw in the settings when i go on sound category i can't select the output and input device..)
Hope someone will help me.