AVI Files

Hello, this is my first question ever on this newsgroup, i have AVI video
files that dont seem to want to play on my Windows Media Player, I have the
Lastest version of WMP, WMP 11. i downloaded the codec package for WMP, also
downloaded AC3 Filter and all the Player does is just give me audio, there is
no video whatso ever. Can somebody help me or point me in the right direction?