Failing that, download and install the Codec pack for WMP.
http://www.xpcodecpack.com/
I also use FFD Show and Xvid decoders. My WMP plays anything i throw at it but tbh i cant remember which i installed first as i set it all up a long time ago.
install the Codec pack first then the others int he order i have typed them.
Failing that, PM me if you want a fully working version of Power DVD 6