I have a 2010 iMac 21.5, i5, 3.6 GHz, 4G, 1T. When new and the first yr or two, before I would go to bed, I would turn off the power surge protector where the iMac and other hardware was connected. After a few yrs I realized that it would take longer for the iMac to "power up." Now, I leave it connected to the power surge protector and on so I won't have to worry about this. I disconnected the iMac this past weekend to clean the room and connected it back on Monday, but it won't turn on now. Does it have a "power pack" inside that needs to be "charged" before it can be turned on? What exactly is going on here? Last time it did this it took days before I could turn it on again. Assistance is requested. Thanks!