Cant play my game, need help

[iTz iWnDeR]

Im playing The Sims 3 on a windows 7 dell, and i have checked my requirments and everything matches perfectly, i pass everything with flying colors but as soon as i try to play thr game, regular Sims 3 or World adventures, it lags so bad i cant even play... all of my settings are all the way on low, and i dont know what to do. im hoping its just because windows 7 is sort of new, but someone please help me. {wacko}