I recently assembled my HTPC and bought a nvidia gt9400 with native hdmi out to connect to my Samsung lcd tv. My old pc did not have a spidif connector to connect the graphics card to but I tried using a analog
connector to the tv to get sound but I was getting no sound when the audio was plugged into the tv but i was when it was plugged into the tv.
If you are experiencing this problem YOU ARE NOT ALONE Nvidia has made a hash of their drivers and the hdmi connector is tricking the tv into thinking that the hdmi cable is sending sound even though it is not thus making the tv ignore the analog sound input.
The solution can be found here : http://forums.nvidia.com/index.php?showtopic=99932 it is semi technical so if you are not very experienced you should possibly look at getting an ati card as they get sound through the pci connection ( or so I hear)
Hope that helps
Mitchell