I've been trying to format a macbook pro with the mac os x 10.4.11. I insert the installer disk but it doesn't read it. It just ejects it after a while. I restarted it and hold C but it just ejected it again and nothing happens. I also tried holding the option button as it started up but it ejected it once again and then only the HD icon shows up. It is the disk that came with the macbook so i don't understand why it doesn't work so i would appreciate if someone could help me. Thanks in advance.