HDMI help

Hello,

I have a connection from my computer to the TV via an HDMI cable. When I go to hook it up and watch on my TV, the sound only comes through the computer. I went to my sounds and there is nothing there for the HDMI sound. Only options are: Regulat Speakers, Dual Headphones and SPDF-HP Dock. How to I get the HDMI to show up. And yess, all disabled devices are shown.

Thanks!