I have an AverMedia ATSC tuner in my Touchsmart PC.
Recently we moved, and I had the tech activate one of the coax jacks near the PC and I ran the cable into it.
I couldn't get any channels with MC15 but I get about 22 with WMC. I don't have a box but I though I'd get more channels; it's almost like it is in ATSC antenna mode or something....
The tuner is set up correctly in MC as far as I know; digital input to the correct tuner.
I'm not a TV guy.....