I'm having an issue with my PowerBook G4. It wouldn't turn on at all before, so I installed another motherboard. Now it will power on, but it only shows this folder icon that blinks. I'm a complete n00b to macs. If this were a PC I would of fixed it by now. I need some help. I've tried the installation disk, but when I hold down the C key, it takes longer, but it just shows that folder again. When I hold down the Option key, it only gives me a reload button, and an arrow button, but no boot up options. Do you think it could be a problem with this other used motherboard? Or is it that I just didn't put it in right? I've double checked all the hardware, and it seems to be all connected. The keyboard lights up, and the trackpad works, and it makes the boot-up sound. Please help. I'm completely lost.