I've never worked on a MAC before, but I have a G4 PowerBook that when turned on goes straight to a screen with a Folder that has a question mark. From what I read this means the boot loader or OS is corrupt. I placed the restore disks in the unit. It seems that the unit will not read the CD. I took the hard drive out and placed into another machine, so I know it's okay, but I'm not sure about the internal CD drive. Is it possible to boot to an External CD-ROM drive. I only have a USB, but I have been advised that I will need a Firewire. Any help or pointers would be appreciated.