Thanks ALx330; I get it now. I think what threw me off was when I selected a movie from the i tunes store. It gave me this message;
The HD version of this item is available on Mac or Windows 7 computers with HDPC components.
After I read this, I thought I needed a computer with HDPC capability. I think what this message means is, if you wanted to be able to watch HD movies from itunes on your computer, it would have to support HDPC. (I guess) thank you very much for the help!