DannyPleasant That's good but also a bit disappointing, in that a missing entry would have explained the problem. At any rate, please uninstall Sims 3 with Revo Uninstaller (the free version is fine). While you're at it, uninstall the EA App as well, using the Intensive scanning method.
Reinstall the App, and create a new folder on the root level of the drive of your choice. For example, C:\Games is fine, but not C:\Program Files\Games. Install Sims 3 into that folder and try to play.
If you use a third-party antivirus, please disable it (temporarily) while installing the game, and don't reenable it until you've tested once. As long as you don't do anything else at the same time, your computer should be safe. If you can play, you can reenable the AV, and set exceptions for TS3.exe and Sims3Launcher.exe.
