Hello, I just purchased a new 20" imac and am new to os x but think it's great. However, I'm having a problem with scheduleing the power on and off feature in the preferences. It's not working. At all. It doesn't power on when it should, and doesn't power off when it should. I've tried to look for an answew on apples website, and they do mention an issue about how the settings might not save if you hit the lock, but that doesn't seem to fix it. Anyone have any ideas on how to correct this?