Making this a sticky and locking as it is very helpful. there is no need to uninstall your sims 3 game just follow these steps.
I have seen a lot of people dealing with issues in their games & having to uninstall & reinstall... This is not necessary my friends... There is a shorter, easier route to take that will reset your "Sims 3" game folders to factory...Here are the instructions:
(This is for windows 7 users... For all others, the concept is the same, but the folders may be stored elsewhere)
Locate: Documents>Electronic Arts>Sims 3
Rename: "Sims 3" folder to "Sims 3 Old" (The same folder you put your mods, downloads, ect...The whole folder... Just rename it... Won't hurt a thing...)
Locate: Your "Sims 3" Launcher icon... Right click on it & start your launcher using "run as administrator"... Once the Launcher is loaded, Start the game & go all the way to the Next menu where you can start a Game... After it has completely loaded to this menu, Exit the game entirely...
Locate: Documents>Electronic Arts>Sims 3 old
Copy & paste your saves, mods, downloads, music, ect... to your new folders located at Documents>Electronic Arts>Sims 3
Locate: Your "Sims 3" Launcher icon... Right click on it & start your launcher using "run as administrator"... Once the Launcher is loaded, you will see all your SC & CC & w/e needs to be "reinstalled" into your actual game... Moving these folders does not reinstall them, simply keeps you from having to re-download them from the purchase history on the sims3.com site...
DO NOT REINSTALL YOUR DOWNLOAD STUFF ALL AT ONCE! REINSTALL THEM IN SMALL CLUSTERS LIKE 5 OR 7 AT A TIME! It's a hassle but far less trouble than uninstalling & reinstalling the entire game.
Subject: how to reset your sims 3 game 
Mon Sep 03, 2012 6:15 pm
: I never thought of it that way. :
: :
: Really useful!!!:
: Thank you sooo very much...I apperciate you doing this my bfff!!!:
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