Search for AVI file?

[John Doe]

I realise that this is not really a python question, but python's the
only language I'd be comfortable trying to deal with this.

What I need is to search a drive and find all the AVI format files
that are NOT listed with the AVI extension.  I'm looking over an old
drive of mine from an old computer.  I know the files were renamed
with the wrong extension, but I know that they were originally AVI
files.  Can python do this for me?  Any hints?  Anybody have a link to
something that would already do this?  I appreciate any help.