Hardware: 1.83 GHz Intel-based 17” iMac
Symptoms: Spontaneous shutdown (possibly), subsequent attempts to reset and/or boot the machine using the hardware switch in the back do not work. Sleep light comes on as if it will boot, then blinks rapidly and indefinitely. No fan or HDD spin-up heard; iMac appears dead.
Solution: Unplug all the cables and power cord. Place the iMac screen-down on a soft surface with the bottom of the stand facing you. Using a phillips-head screwdriver, open the access door in the bottom of the unit. Completely remove all RAM sticks from their slots, and reinsert them into the slots, making sure they’re properly seated. Apply additional slight pressure to ensure they are fully inserted; there may be an additional millimeter or two of space below the RAM stick’s pins. They should make a quiet “snick” sound as they’re pushed into the connectors to the full extent. Close the access door and place the unit in its upright position. Reconnect the power cord and all cables. Bickity-bam, resurrection.