For example, when I first got Moncha I started playing with the scene settings and output settings and size settings and all kinds of things. It didn't take long before everything was all out of whack. It would have been nice to have a "Restore Default Settings" menu item that would take everything back to how it was when it was first installed. Perhaps, you could add the default.mws file as an embedded resource within the program and if someone wants to restore it will just overwrite the default.mws that is stored on disk.
Sorry guys for the problem -yes, you have to completely uninstall old version and install new one.
Sometimes for me it's really strange, why is so hard to do even easy tasks like installer good... Maybe I should ask engineers at Microsoft ... Sorry again for the problem - one dll library is not reinstalled when upgrading. That's why you have to uninstall and install new version.