Unable to start, please reinstall base game?

So I was updating my game of Sims 3 and it terminated the update. Then when I double clicked the icon to try to open the launcher it said:"Unable to start, please reinstall the base game." But it's already installed and everything on Sims 3 is up to date. Even everything on my computer is up to date. So I went to C:\Program Files (x86)\Electronic Arts\The Sims 3\Game\Bin and clicked on Sims3LauncherW and the launcher opened up but it said: "Error, your Sims 3 Base Game is incompatible with the current Sims 3 expansion pack. Please update your game via the game launcher." That really confused me because I don't even have any expansion packs. So I clicked OK and it took me to the Game Updates tab. But it said"Your game is up to date."Then I clicked Refresh just to make sure it was right and no new updates showed up. I then clicked play but a little error box popped up saying: "Unable to start game. Your Sims 3 Base Game is incompatible with the current Sims 3 Expansion Pack. Please update your game via the game launcher." Same thing as before! I was really having fun playing Sims 3 and I don't want to lose my game. What should I do?