My 2010 iMac won't turn on. I used it the day before, then turned off the iMac and power protector. Today, after I got back from work and turned on the power protector to use the iMac, but after 4 hrs it doesn't turn on. It usually takes about 45 mins before the iMac can be turned on. I left the power protector on all last week and the iMac turned on right away. Any advice is appreciated.