The message I get on WM10 is
Windows Media Player cannot play DVD video. Open Display in Control Panel, and then lower your screen resolution and color quality settings. To view the DVD Troubleshooter, click More Information.
Changing the display settings do not work. I have update the graphics driver (Intel 82865G Graphics controller) and I have ensured Direct X is up to date and still no joy.
I do not run netmeeting and cannot find any terminal service clients running.
The only thing I havn't done is downloaded Micosoft DVD Codecs as per link, but surely that would have been part and parcel of WM10.