hello i have been having an issue with hdmi audio .. it just doesn't work

i install the stock drivers from the mb cd and i select nvidia hd audio from the drop down menu and the first tab its shadowed out meaninng i cannot place an icon on the taskbar or change the volume. i hit apply and open a hd video which the video plays but no sound not even youtube sound works. audio comes out of the headphones jack but thats not what i want.

i have tried different versions of the driver 1.0.17 .23 .33. and .41

none of seem to work wondornig if someone here has solved that issue or knows how to make it work i am thinknig about vista 64 bit edtion.. i really don't want to do it but i dont know