My iMac was in "sleep" mode all day while i was at work. It started raining really bad and my roommate sent me a text saying that our apartment had a power outage. When I got home my iMac was off and wouldn't turn on. It had been plugged straight into an outlet not into a power strip/surge protector. Bad idea!
I did some research and saw some other posts on ifixit and ordered suction cups to pull off the glass and see if plugging in the power cord gave any indications anywhere inside. Nothing. So i decided to take a chance and ordered a power supply thinking that would do the trick.
The repair took 40 minutes and the guide gave the exact instructions I needed. Nothing weird or out of the ordinary happened thankfully. After I was finished I plugged the iMac in and my good friend came back to life!
Buy a surge protector and plug your Mac into that so you don't have to spend $140 to bring it back to life!