If your sure its not a codec problem (Even if you think its not, you might want to install the latest divx, xvid, and ffdshow codecs on your computer. You can find the links in numerous places on the forums), then this is what I suggest you do. Uninstall the Windows Media Player version you have now, and then install the latest version (9.0) from here (depending on what OS you have). If it still doesn't play, then I suggest you use a different player such as RealPlayer or VLC Player. Hope I could help.