The launcher poses problem for lots of people.
If you just want to play the game and are not worried about the custom content, go to C:\Program Files\Electronic Arts\The Sims 3\Game\Bin (default install *path) and run TS3.exe.
This runs the game without the launcher and should get you in without the need of the launcher.
If this fails, try right clicking your shortcut and click 'run as admin'. If the problem still occurs and you can't play the game, try a re-install.
If that also fails, the problem is probably hardware related.