I acquired an iMac G4 flat panel 800mhz which will not boot-up. When the power button is pressed, the tone plays, the small led on the screen illuminates and after a few seconds there is a slight flicker on the screen then nothing - just a black screen. I can hear a fan running inside. The cd tray will not open, if I gently turn the drive gear, the tray will manually open but doesn't seem to be connected to any power - there was a Tiscali Broadband startup disc in there - I don't know if this is significant. I'm just trying to figure out which piece of hardware (I'm assuming so far that it's hardware) is at fault or how I can fault-find. Is the tone generated by hard drive boot-up or is it hardware driven? Also I've tried all the reset procedures I can find but still the same result. I've had the base off, checked all connections, everything looks clean, back-up battery seems ok at over 3 volts. Any advice or suggestions welcome.