Sims issue! Help 10 points.?

I bought the sims 3 and it seems like i cant start the game because when ever i try to play it . It says that i need internet connection. Today i bought the sims 2 as i cant play sims 3. Is there going to be any problem with sims 2 aswell? Do i need to register sims 2 online atfirst? Why is this happening?