Re: SIMS 3 BASE GAME WORKS BUT NOT WITH THE EXPANSION PACKS!!
@ErinvanWyk The specs of your computer matter here, which is why I asked if you could run a dxdiag. That will contain the relevant information without your having to hunt it down.
If you've uninstalled one or more packs, you need to clean the registry before trying to run the game again. If you didn't do this, it's probably why you can't launch even the base game. At this point, it might be best to completely uninstall before proceeding. You can clean the registry manually (see below) or with a tool like Piriform's CCleaner.
https://help.ea.com/en-us/help/the-sims/the-sims-3/manually-uninstalling-the-sims-3/