I might have misunderstood but what I think you need is two tools called Avi4cc or Div2Mp4. These are the only two utilities I know that can change the codec used to play a certain file. Since all avi files are the same except for the codec used(same container) they are all basically interchangeable except a few which use a different filter altogether(So this is basically trial and error-i.e. note down old codec, change codec and play. If it works, problem solved otherwise change to something else or old codec[original]).
Hope this helps.
P.S. Sorry if this is not what you were looking for.