I just did a new build and the HDMI cable works from my video card to my TV, but I get no sound. It doesn't work from my ASRock Z77 Extreme 4. No picture and no sound. I installed everything on the disk that came with it. Can anyone help me?
You said that you have a dedicated GPU card, so that means that the HDMI port on the motherboard will not work unless you remove/disable the card and use the processor's integrated gpu. If the sound is not working with the HDMI cable, then check to make sure you audio output device is set to HDMI on your card. You can do that by going to audio settings in (I assume) Windows.