@indycutie I see the dxdiag, and I also see why Sims 3 might be lagging: your computer is quite underpowered for the game. That doesn't mean you can't play, obviously, but it does mean that you'll need to lower the overall load on your computer as much as possible. So that means not running anything else alongside Sims 3, not even a browser. Playing while offline can also be helpful, so please try that if you haven't already.
And unfortunately, any issues with the game will be exacerbated when you're running a well-progressed save, which will take more resources to run than a new one, or playing in a world that has its own issues, or even playing in a full or overstuffed household. Running NRaas StoryProgression also increases the game's resource use.
There are a number of tips here that can help:
https://www.nraas.net/community/TIPS-FOR-BETTER-GAME-PERFORMANCE
I don't think there's really much you can do beyond the above, at least not with your current computer. But even small changes on the margins may make the game playable again.