I have recently installed The Sims 3 on my PC will all the expansions, excluding the katy perry and the "singing one", so everything up to Master Suite Stuff.
I have the game updated to the latest update available but whenever i play for a couple in game days, the game will start to lock up so, all actions will freeze but trees, water, ZzzZZzz, etc, will still move.
I can do the "resetsim *" command and it helps for the next week in game, but then it starts to freeze up again.
many people seem to have this issue, but i have not yet found a permanent solution.
my system auto defrags every week, so i know it is not that, i believe that it has something to do with the game itself, because when i resetsim*, it just set the sim back home and reloads their stats and then it runs fine for a while.