Ursprünglicher Beitrag von: Marcy ,
Hello, I just went through this (today) with my 20" iMac Core 2 Duo after replacing the RAM. If you've replaced the RAM or taken them out for some reason... What worked for me was to unplug, take the RAM out re-insert, hold power button down for 5 sec. plug back in and was good to go! Good luck!