Originally Posted by
BigMouthBillyBass
Fuck WMP off as it's spyware laden DRM trash (well, so is Vista) and use Videolan
www.videolan.org
it plays everything you throw at it and isn't total bloatware

Use VLC as above, but if you must stick with WMP, try downloading this
Mega Codec Pack -
http://codecguide.com/download_mega.htm
I've used this on countless machines and its been fine. In conjunction with VLC, my watching habits have been pain free.