With regard to the "Intel HD audio" thing, it looks like cascade is right, the hdmi audio device on my graphics card clearly appears in lspci as something else entirely.
So it does seem like "intel HD audio" you are seeing is the onboard sound. I've no idea why you can't disable it. Can you post the output of this:
As to the video, if you have a core i3 or i5 which the board you have is designed for - that's why you can't disable it. It's integrated into the CPU. You disable that by selecting pci-e as the first device as you have done.
We need to know more about your hardware before any other useful suggestions can be made.