Thanks Alex but looks a bit complex for me. I'm worried about losing my playlist (473 files) and setup details. Not sure yet how I can safely copy these details and re-import them. I have spent HOURS trying to sort this Visualization loss and I think perhaps I need to spend many more hours learning the complexities of MC.
What did happen before you lost the display options?
If an uninstall/reinstall helps it is much faster than spending hours trying to fix a broken installation. (What did you actually try to do?) Ticking a few checkboxes in MC options doesn't take very long either.
In my opinion those instructions are not very complicated. There are a few simple steps. I am pretty sure that they are safe and preserve all previous user data.
All MC playlists are included in the library backups. (File > Library > Backup Library). Actually, I would recommend making a library backup every time you have made library changes. It takes only a couple of seconds.
After a complete uninstall the configured options are reverted to the default. That is why I asked to make notes about them before uninstalling.
P.S. I suppose you have already tried to reinstall MC on top of the old installation. It is usually the first thing you could try. Sometimes just a reinstall can fix things without any further steps.
EDIT
In case you have stored media files in the program folders (which is not a default place for them) you must of course backup them separately before uninstalling and possibly deleting the folders.