Pany PT-60LC14 with HDMI PC hookup

Ok, I called panny on this, and they told me that HDMI port is for set top boxes, not for a PC, but I purchased a DVI to HDMI cable and hooked my pc up to the HDMI port. I do get picture, but it is HUGE in 720X480 res, and my video settings on the PC wont alow me to change it to any other res. I wanted to know, if anyone has figured how to use the HDMI input on the screen? I used RGB, and the resolution is just way too large to live with, at 1024x768, at least to do any gaming on it.


Any hints much appreciated. Got a ATI's latest and greatest, video card on the pc.