It will take over for the on board audio. If you want to use that, you have to make changes in your audio properties (forgot exactly where).
The Realtek HD audio needs the M$ 'HD Bus driver' installed first (2k & XP). Of course, there isn't a damn thing from UnRealtek or the manufactures of the devices (video card, MB etc.) that even hint at this except mention of the HDMI audio issue with these 2600 cards..
Both issues are hidden in the M$ KB.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.