You didn't mention which version you had, just that you have all the expansions.
If you have the pre-2012 disc version of the game, just uninstall and reinstall the Sims 3 base game disc. This should reset the launcher.
However, if you have a 2013 and newer version you will need to repair game through Origin.
If that doesn't work, you should be able to uninstall and reinstall the game through Origin. It will uninstall the whole game, and then you'll want to then install the whole game again through Origin.
The post linked below has how to uninstall and reinstall the game regardless of if you have the disc version or Origin version.
How to Install and/or Uninstall Sims 3, Expansions and Stuff packs
http://www.carls-sims-4-guide.com/forum/index.php?topic=20732.msg425178.html#post_Uninstall