First, make sure your computer meets the minimum system requirements to run The Sims 3 game:
- Processor: 2.0 GHz P4 or equivalent;
- RAM: 1 GB;
- Video Card: 128 MB with support for Pixel Shader 2.0;
- The latest version of DirectX 9.0c
- OS: Microsoft Windows XP Service Pack 2 or Windows VIsta;
- HDD Space: At least 6.1 GB of hard drive space with at least 1 GB of additional space for custom content and saved games.
If the requirements are fulfilled, uninstall it, run CCleaner and install the game again. Also, update DirectX utility and your video card drivers. If you still have issues, try to find another solution using the official forum.