I have avi videos I got off of bittorrent but when I try to play them I get the error message: Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file. I also have the program that shows you what codec you're missing and that also brings up a message saying that it doesn't recognize the file. I'm out of ideas because out of the 20 or so episodes only 3 work and the rest are codec'd.
what version is your media player.on 11 you open media player,right click on the icon in top left corner,and go to tools,then options.under plugins check the box that says download codecs automatically.should help.
You can also get a program called Gspot it will tell you the info you need about the type of codec you need for that avi file. http://www.headbands.com/gspot/download.html
It was long time ago, probably 3-4 years ago but I used Cucusoft AVI to VCD DVD MPEG Creator Pro when I tried to convert avi file. I had no problemo at all, just followed the directions.