Sims game not working. :( :(

I have the sims 3 and a few expansions, and have never had trouble with the game until now.

I recently downloaded the sims 4 free 2 day trial, and since going back to my sims 3, it has crashed and is not working. (Not sure if they have any connection, just thought it may be worth mentioning) 

When the game menu loads, I click the my household. When that household loads, it zooms in to the last character i was playing, and you can see the other sims on the house (one is sleeping, one is on the computer and one is at the science table) but it wont let me click anything or do any commands. There is no other sim icons to change to to control the other 3 people in the household, and when I use the spacebar hotkey to change sim, it zooms out to the roof view..
After a few minutes, an error message comes up that says "Sims 3 has stopped working"

This happened for the first time a couple of weeks ago, so I closed sims and steam, and hoped that it would be fixed when I reloaded it, but it wasn't, so i made a complaint to steam, and they sent me a link for here instead.

If anyone knows how to fix it, I would really appreciate some help.
I don't know anything about computers, but I can tell you that I have been playing this game on this laptop since it first came out and have never had a problem.