You might be knowing that Windows Media Player can’t open / play the .avi files.
This is just due to the reason that the codecs needed for playing the .avi files doesn’t comes installed with the Windows Operating System.
So, the easier solution to this problem would be to install the necessary codecs.
Now there are two ways,
1. Download the K-Lite Codec Pack, which is basically the combined combination of several media packs. And in terms of productivity it is the best solution to play almost any media file using the Windows Media Player.
2. The second method could be downloading the Divx Codecs, which could be used to play the .avi files onto the Windows Media Player.
Enjoy Yourself.