I recently replaced the memory, the upper case (including power thing-y, trackpad, etc) and also put a dvd-rom borrowed from a pc (panasonic sr 8176c) in an ibook g3 500 i inherited. When i put it back together (proud to say only one mystery screw left over), the power button gets no response at all, though the all-caps button on the keyboard will light up when pressed, so power is getting through somewhere. I took the new top case off and plugged the old one back in, though without putting the whole darned thing back together and still nada. I took it all apart again back to the optical drive and checked the connections including a cable that looks like it is connected to the power plug, pressed them to firm up the connections, put it all back together and... still nothing - not with the battery - which has a charge, and not with the power brick which works. Any ideas? I tried pressing the reset button, and that didn't work, though I will try it again with the battery and power brick disconnected. am stumped and am afraid I am going to break something taking it apart over and over - the gray internal frame is already broken in one place and the metal covers on both top and bottom are starting to look a little crumpled in places. Thanks!