download klcodec, although you may already have a divx encoder the media player that comes with klcodec will allow you to watch it (i had problems with windows media player 11) http://www.codecguide.com/download_kl.htm is the link to it
klcodec is a codec pack that comes with several codecs in one as I forgot to mention. the codecs work for pretty much every video type, where as vlc is a media player that comes with a divx codec built in klcodec full comes with a media player built in and overall has more support, one of the many codecs that come with klcodec is in fact divx itself which is a .avi codec.