Try deleting options.ini, in Documents > Electronic Arts > The Sims 3. If that doesn't help, move the entire Sims 3 folder onto your desktop, and a new folder will spawn when you open the launcher. Don't add anything to it, and don't change the graphics settings, until you've loaded the game and had a look around.
When you do want to change a setting, be sure to do it at the Main Menu and then quit to desktop before loading a save. Not doing so is one cause of significant graphics glitches. It's safe to change the resolution and switch between fullscreen and windowed modes, but that's about it.