Can someone explain to me the difference between the various sleep settings? Put the computer to sleep..., put the display to sleep..., put the hard disk to sleep...? What is the difference? Right now I have all of mine enabled on my MacBook- is this a good idea? What is the best way to have it set up? Thanks. Sometimes when I wake my macbook up from sleep the log in screen won't appear and I will just have a black screen where I can move my mouse around until I close the lid and re-open it. Could this be because of my sleep settings? Thanks.