The sims 3 on steam problems?

ok i just downloaded steam about 3 days ago. the first game i got was sims 3 with most of the expansions. i let it download 100% but when i go to play it steam stops responding and closes out. i uninstalled sims and re installed it, and same thing happened. im kind of getting pissed as i payed allot of money for all of the stuff. any one know what i should do? im probably going to contact steam about it soon if i keep having problems.