"There was an error during startup. Please see the Log for more details"

I just downloaded supernatural, getting ready to download the new seasons. I've never had a problem playing before and then I went to click on the start up screen, this popped up "There was an error during startup. Please see the Log for more details," and the game then crashes after i click okay, since it is the only option. I then got mad, uninstalled everything because that's what i heard other people did and i installed the first sims 3 again fine, then an update appeared, i updated it, and then the same error popped up. I then again uninstalled and reinstalled and tried to go on without updating it and adding the rest of the expansion packs i have but until you update it you can't go any farther, now i can't play at all. SO frustrated and I am computer illiterate. HELP!