Realone Player 10 AVI files

I just had to re-install my operating system and re-download Realone Player. It won’t play the video part of AVI files but it will play the sound. I don’t get an error message or anything, but the screen won’t come up. Previouly I had this problem and downloaded something from a site, but I cannot remember what it was. I have DivX Pro Codec Adware, but this does not help. Thanks to all who have a reply.