Removing Unwanted Genre's

I don't know how it happened but I seem to have every Genre known to man in the Genre: drop-down list box. I wish to remove most of them. Problem is when I go to Tools > Options > Genres there is only 3 Genres in the user-defined-genres list.

I don't know if something is corrupted

See attached screenshot

Any solutions?

Nothing is corrupted.
These are the predefined extended genres of ID3V1:

There is only one way to get rid of these genres:
Enable: Show only user-defined genres
and define genres that you want yourself.
I never tested if these selfdefined genres are the same as the predefined in case they have the same name.

Thanks Much appreciated