No Sound with HDMI connection

I've just built my first computer, and everything works fantastic, except that when I connect my PC to my HDTV through HDMI, I get a crystal clear display but no sound. I can plug in headphones and hear everything that way, but that is my only option right now.

It is curious because I have installed a Radeon HD 5450 video card with an HDMI port. I installed the DVD driver (Version A8.98W) and the visual sizing was fixed, but like I said no audio. I've checked the playback devices, and my TV seems to be listed as "AMD HDMI Output", which wont play sound (even if I set it as the default device) . I've also checked the Device manager and seen that "AMD High Definition Audio Device" is listed under "Sound, video, and game controllers".

The only way to play sound is to disable the AMD HDMI Output and plug in headphones so that the audio is playing on what the PC thinks is speakers.

Anybody ever seen this before? Any help would be greatly appreciated.

I downloaded the very latest driver from AMD (Version 13.12) and I get the same issue.

On a side note, my display ONLY works if I plug into my video card output. My motherboard is a ASRock Z75 Pro, which has its own HDMI port, but no matter what I do if I plug HDMI into that port, I get no display and no sound. I am thinking these problems may be related. Any ideas?

Already tried removing the video card, even with no video card I cannot get a visual display via the built in HDMI port.

The motherboard does have a built in VGA port but I don't have a VGA cable to test with. May have to invest in one for troubleshooting purposes.

Yes fireberd is correct about both of those, I also have used this hdmi cable to connect other devices to the TV with complete success, so I have ruled out a bad TV and cable.

volume control shows the "AMD HDMI Output" when it is enabled, but no sound comes out. I have to disable the HDMI Output in order for sound to play on "Speakers" which is what my headphones are plugged into.