Cannot run my sims 3 game?

okay, i had the normal sims 3 disc installed on my computer along with the sims 3 generations. I just tried to install the sims 3 late night. it installed perfectly fine, i then updated my game cuz it prompted me to. but when i try and play it says "No game disc found! Please insert The Sims 3 disc before proceeding." i push cancel because the only other option is retry and when i do that it just repeats the same error. but when i plush cancel it says "the process could not be started" why is it doing this. and how can i fix it?