No, not if you move your Sims 3 folder to the desktop or some place safe and rename it. (This will help make sure game saves, options and things like that are safe) - I copied the text from the Factory Reset link. Just in case you want to have a read. I do this quite a lot with my games, just cause I like things to run smoothly.
MrsFlynn
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Factory Reset
[This is different from a total-game reinstall - This just sets the game back to factory default.]
Move your Sims 3 folder to the desktop or some where safe, and rename it something like Sims 3 Current. Click the Sims 3 icon to create a new Sims 3 folder.
Go To: ----> My Documents > Electronic Arts > The Sims 3
If you want to continue to play your previous game-saves, go into the Sims3 folder that you backed up and copy over your game saves, files and such over to the new game to see if that helps.