Since the repair did not work, and you are considering removing Windows Essentials (WE), I would try doing a System Restore
, that should take the worry out of whether or not your WLM will revert back to its original state. It will also remove WE. Just pick a time, and date to before you installed WE.
If you haven't already, make that backup of your contacts, accounts, and messages.
There has been much discussion about the newest version of WMM not being as good as the older WMM6 because Microsoft (MS) stripped a lot of functionality out of it.
As for alternatives to WMM for windows 7, do a search with those terms, and you will find a lot of alternatives even some that are open source.
Here are some that I found:
Windows Movie Maker Alternatives - Better Than Windows Movie Maker
list of free movie maker downloads
Movie Maker | Open Source Alternative - osalt.com