@johnnyOdonny94 if you have the games running through Origin, then your game is registered and the code can be found under game details (right-click on the game in My Games - choose 'view game details" and you will see Product Code). If you have an older version than that, you can find the code in the registry as detailed in this link: http://answers.ea.com/t5/The-Sims-3/FAQ-Lost-and-broken-DVDs-and-missing-serial-codes-What-to-do/td-...
However, I would suggest that you look into the reason for why the game is crashing before you proceed to do a complete reinstallation (which often proves to be futile and a great waste of time).
1) Has the game ever run well before and if so, have you then installed mods / CC lately?
2) If it has always been crashing since you started it, please post your dxdiag: http://answers.ea.com/t5/The-Sims-3/HOW-TO-DxDiag-for-Sims-3-PC-Only/m-p/1049584/thread-id/47181
Let me know how it goes!
