I have the Sims 3 and the first expansion I installed was Late Night. I make a YA female and bought her a small apartment. Then I try and take her to a bar and the entre game freezes until I get a message saying the bar has closed.

Then I try and have her throw a party for her adult birthday. As soon as everyone is in the house, the game freezes again and I can't even age up my sim or make all the people go away. Even now when I try and throw a party in sunset valley or twinbrook the same thing happens.
I'm really disappointed because I was really looking forward for this game and now I can't even use the great city it comes with or throw any parties. I tried uninstalling and then reinstalling it but it didn't work. Can anyone help me?