Break the GRUB start-up password

First, boot the system with the first Linux CD, when you see boot prompt, type linux rescue to switch to rescue mode. Here, you will be asked if similar steps should be followed, which need to be followed in the installation.

At the prompt, type the next command:
# chmod /mnt/sysImage
# locate grub.conf
# nano /path/to/grub.conf (Edit the grub.conf file and remove the passwd line from the file)