LiaKnow Sorry for the late-ish reply. Your dxdiag doesn't list any Sims 3 errors, and there's nothing obviously wrong elsewhere in the file. Your Nvidia graphics driver is somewhat old, but please don't update it yet—there are some issues with the newest drivers, and your current one should work fine with the game.
Instead, please try forcing Sims 3 to open in windowed mode. Open Options.ini, in Documents > Electronic Arts > The Sims 3, search for fullscreen , and set it to 0 (zero).
If that doesn't help, repair the game (if you haven't already) and also move the entire Sims 3 folder out of Documents > Electronic Arts. This will allow the game to create a clean folder with no content. Let me know whether this lets you get far enough to start a new save.