Bigrick, I had the same problem as you. Here's a fix that worked for me. It's the graphics card. Nvidia will not let you run a dual display for HD content. I had a 8600 and switched over to the Radeon 2600 HD and now everything works. I run a dual display at different resolution, one RGB and another DVI to HDMI. I also use My Movies, the lastest version....try that.
Bigrick perhaps this is the answer you are waiting for! I have been using ATI HD2600 Pro and 3650 today and soon 4650