I thought you need a decoder(software or hardware) if you wanted to use WMP8. I found this in the help file:
<<
To play DVDs, you must have a DVD-ROM drive and a software or hardware DVD decoder installed on your computer. If you do not have a compatible DVD decoder installed, DVD-related commands, options, and controls do not appear in the Player and you cannot play DVDs. >>
Since you're using XP I assumed you were talking about your
Main System. I would have thought that your video card came with a DVD player, maybe one is available at the manufacture's website. Good luck