My iMac refuses to sleep no matter what sleep preferences I set or even if I try to sleep it manually (apple>sleep). It doesn't do anything. The display doesn't even dim like it used to a week ago. I don't have anything plugged in but the keyboard and regular mighty mouse, and restart doesn't change anything either. The Apple store installed a new hard drive on the computer a few days ago, since the 1.5 year old one randomly crashed and died. (AHH!) So I don't know what kind of funky things they might have changed, I'm just wondering if there's any simple maneuver I can do to make it sleep like it's supposed to!! Thanks!