Duplicate tracks played and in LMS

I have looked at a couple of threads here but they don't answer my problem.

The Touch is playing duplicate tracks on certain albums and LMS shows these duplicates.

I do not use iTunes and never use playlists.

WMA has automatically created duplicates but so far as I can tell LMS doesn't link to WMA.

I have rescanned but the problem remains.

There is only one music folder.

How do I remove the duplicates? (One album is stored 7 times in LMS but only once in the music folder it's pointing to!)