have you set your default audio source in your OS? if so, what type of powered speakers are you using, or are you using the optical out ? do your headphones work in the audio out ports?
Asus Rampage IV GENE
i7 3930k @ 4.8 24/7
custom loop
16 gigs Trident X
HIS HD7970
2x OCZ Vector 256gb raid0 via UEFI
Crossover 27Q
Win8 pro