522 Views 4 Replies Latest reply: Dec 10, 2012 3:39 PM by Xlim17
See here about fixing grey screen at startup.
Did you add any ram recently?
If yes, it could be incompatible ram.
Remove it and see if the iMac will start.
Any new peripherals?
Unplug anything that is connected to the iMac and see if it will start.