Bought it used and broken for 100$ to fix it. It tries to boot, the fan goes on high and then it shuts off. Then it tries to start itself again. I have tried putting more heatsink goo. I have reset the PRAM and the logic board (took out the little battery). I took out one hard drive, then the other, checked the RAM. The antenna's are broken. Already ordered new ones. Is it the logic board? I am afraid of getting a new logic board and then having it be one of the hard drives. I have an additional PowerBook G4 mac. Oh, also, so when I turn it on, the fan slowly gets louder and louder, then there's a 'CLICK' and then the whole thing shuts down. help? I think it's 2.56gz, 4 gigs of RAM and 1 TB of hard drive space.