I have a 17" G4 1Ghz iMac, we used it until 10 months ago when I got my new 24" Intel 2GHz machine. Well; That new 24" iMac is now in the basement craftroom as the digital hub for pictures/video/etc, while I brought the 17" G4 1Ghz iMac out from my closet for the upstairs loft general web surfing machine. It worked for 2 days and upon shut down would not re-start. I could only hear the fan and nothing else. If I held the power button for 10 seconds upon trying to start up there was a chime that sounded for a few seconds. Once the fan is making small sound, nothing else, if I hold power button for 5-20 seconds the computer will shot down (fan turn off). Did some online checking, found article on PMU, so I did try and re-set PMU via the apple support article.Resetting the iMac (Flat Panel) Power Management Unit (PMU). Still, no re-start. It was running the latest 10.4.x update upon being put away for 10 months. Here is a pict of the bottom, the red light is on upon trying power on, my finger is on the PMU reset button. Is there any other diagnostic thing I can do? Is there a battery on this logic board that I can check/replace? I'm 100% ok at taking it apart and trying anything to fix it. Any help is appreciated, I don't have $$'s for apple tech, instead DIY.