Laptop/projector display problem

I have an Acer laptop with Windows XP Media Center and a Viewsonic DLP Projector with a VGA cable. Applications (PowerPoint, Picassa, etc.) work fine. When I try to play a DVD on the Acer's built in drive, I only get the frame for Media Player with the controls on the bottom projected. The movie does not play on the projector. The movie plays fine on the laptop screen. In the Control Panel/Display Settings/Identify, I get the "1" on the laptop screen and "2" on the projected. I have the box checked for extending the screen. Viewsonic tech support says it is an issue with the computer display setting not being at the proper ratio. When I had this problem with the first projector I purchased, I exchanged it. Now I have the same problem so I doubt it is the projector.
It is: Acer Aspire AMD Turion dual core
15.4" WXGA TFT LCD
ATI Radeon Xpress 1100
DVD Super Multi Double Layer
2 GB DDR2

Thanks for any suggestions.
Paul H