So my 1.8 GHZ G5 imac won't boot. I used a external hard drive for the first time with it. Locked in the middle of a backup so I restrated. Now it just gets stuck at the white apple screen. After a couple minutes, the fan comes on. Whats up and how do i fix it? I tried to reset the open firmware settings and that did no good. I was stupid enough to leave my system disks at my old apartment so I can't boot off one of them now. My old roommate is mailing them to me, but that'll take a couple days.