I have a .avi file that I recently downloaded. I can't play it any of my media players. They all give me an error that I'm either missing the proper codec or that it is a file that is not compatable. I download gspot and it told me that the file is not a valid .avi file. Can anyone tell me how to find out what kind of file this is? And how I can possible get it to run in one of my media players.

It's possible the file is corrupt or incomplete if you had downloaded it.
Are you sure the extension is AVI? Try renaming to another format.

Try playing it with VLC (VideoLAN Client) and take a look at the file properties.

I tried the VLC player and it didn't work in that player either. I downloaded avimedic and I believe the file is either corrupt or incomplete. Thank you for your help.

DivFix is worth a try. Its a good repairtool for avis.