Hi all, Im new to this forum, but i REALLY need some help with my imac. Its a iMac600 SE. The graphite coloured one. It all started with random sleep modes, the imac would just go into 'deep sleep mode' where nothing works. Ok i could live with that, but now it just wont turn on, and all im getting is a faint chirping noise. Nothing appears on screen either. when i hold down the power button for a few seconds it turns off again with a flash of the power button. Has anyone else experienced this problem? its only 3 years old. and i have no guarantee on it. Im hoping maybe its just the battery that needs changing at the back. All help would be greatly welcomed....