I just bought a asus z77 lx motherboard with an i5-3570k. Everything is running so fast and smooth, but the audio only detects and hdmi device.

When I'm playing a video or something that uses sound, the volume bar goes up, but nothing comes out of my speakers (attached through the rear audio port....that much should be obvious though since the only hardware this detects is the hdmi audio out. I'd guess that it's pushing it out through there, but I'm not really sure, and I have no way of testing that.