Answer to "iMac "Core 2 Duo" 2.4 24-Inch (Al) completely dead. Help!"I had same dead mac issue. I replaced the power supply with a new one and it all worked fine... for about 3 hours at which point the imac just turned off again and would not boot. This time however the diagnostic LEDS were active and I had power, logic and video power. The machine then suddenly started after about 30 mins of staring at the diagnostic LEDS but I got the folder with ? mark in it and it would not boot. Very strange indeed. All LEDS are lit up but it just hangs now on the folder with ? in it. Any advice. 2008, iMac, 24inch, Core Due 3.02GHZ, 500GB HDD, 2 X 1 GIG RAM. Update: As an update. After leaving it unplugged for 30 mins I tried booting again. It gets about halfway through the apple start-up chime and then reboots only again to get halfway through the start-up chime and then reboot again. IT is stuck in this loop. Arrrgh!