Right here it goes, my iMac's had this problem for a while now where if you were to turn it off for the night and you came back to turn it on it would stick to a blank screen, no disc noise and some loud fan whirring after a few minutes, but if I were to wait half an hour and reboot it, it would boot normally and go straight into Leopard. It never really bothered me before, but now this is getting beyond a joke since I'm selling it soon to get a MacBook and I want to solve this problem once and for all. Anyone mind helping me here?