Hi I have an imac. Now I will give you its symptoms and, any input would be great. It will boot after a while online with the airport card and or even offline running tiger 10.4 it will say the computer needs to restart and I need to hold the power button to shut it. I try to put it on again and then it might beep a couple times and the fans sound like they are spinning and the power button light is on but there is nothing on the screen. I have to wait awhile then press the power button again and everything will be ok. Is this the Hard drive or what if you know?