Boot with your bootable CD.
Type 'linux rescue' after 'boot:' prompt and press 'Enter'.
In 'CD Found' window, choose 'skip'.
In 'Choose Language' window, choose 'English'.
In 'Keyboard Type' window, choose 'us'.
In 'Rescue' window, choose 'continue'.
In second 'Rescue' window, choose 'OK'.
Use 'chroot /mnt/sysimage' command to change root file system.
Use 'passwd' command to change root password.
Use 'exit' command to exit from chroot mode.
Use 'exit' command again for reboot.
Remove bootable CD.
Login with new password