Windows explorer crashes when it views AVI files??

Windows explorer crashes when I enter a folder with an AVI file only if it's in the preview pane not whe it's just file details, or when i highlight, or click the avi file. This only happens with avi's and not with other media files. Since then I have done registrly cleanups, system cleanups, downloaded and swtiched over to mozillafirefox, uninstalled IE, ran several virus checks, I don't know what else to do??