Play DivX Movies and more in Windows Vista : In Vista and XP , the Windows Media player lacks support for video codecs such as DivX. This has been a big issue in previous versions of Windows Media players. Playing audio files are usually not a problem. There are issues with other codecs such as Xvid, DivX, Mov and so on. Fix it all with the Vista Codec Package 4.7.x

From: http://www.bestnewslinks.info/tutorials-howto/play-divx-movies-and-more-in-windows-vista/