Sims 3 crashes It kind of, goes orange, then black. Here's my DxDiag, I have no idea what it does. I bought a new set of RAM, as I thought this was the problem, but it's still doing the same.
Try these set of drivers for your computer. http://www.nvidia.com/object/win7_winvista_32bit_186.08_beta.html
Also try turning off Aero as your video card isn't the best and you should free up as much graphics power as you can.