Why won’t my sims 3 game work?

Emily Asked: Why won’t my sims 3 game work?

My computer is brand new I just got it a week ago, and all my sims games are installed on it they have been working fine since I got my computer, but starting yesterday every time I try to open the laucher it says "There was an error during startup. Please log in for more details." So I tryed to just play the game without opening the laucher and it says the same thing, So then I uninstalled and Reinstalled the games and still the same thing please someone help I don't know what else there is for me to do!!! Also it has nothing to do with the sims 3 pets demo I never downloaded that.