Greetings...I have a 24" 2.4 iMac Aluminum that is not "Sleeping" when it is supposed to. When I first got it (30 days ago)...it went to sleep fine. "Sleep" meaning that I have to hit the spacebar to want it. Now after the 25 minute sleep setting (set in the energy saver panel of system preferences)...it is only shutting down the monitor and I can wake the iMac with a movement of the mouse. If I manually sleep the iMac, it really sleeps. I have tried re-setting the sleep interval in the systems prefs to no avail. As I said, it was working early on... Any ideas welcome. Thanks in advance.