When I try to get my macbook to boot up in knoppix from a dvd I have, the computer restarts the mac os 10 system already installed on it. The computer is a macbook with an intel core duo processor and 1 gig of ram. The dvd came free with a book I bought and has fedora and knoppix on it. When I restart my comp. and hold the "c" key, a menu comes up where i can either run fedora or knoppix. When i type knoppix and press enter, the screen goes blank for about 30 seconds before the mac os boots up. Any insight on this problem would be helpful.