You can simply delete the fsdreamteam\zurich folder, there's no need to delete the scenery from scenery.cfg, the installer will of course not create double entries if there's already one.
It's really strange you don't see the entry for Zurich in the Control Panel list of installed program. I hope it will reappear after reinstalling 1.2. If not, even if Zurich might still run ok, it could be a sympthom something is not right on your system.