To break password of GRUB in Linux

Step1 :> Boot from 1st CD or DVD

Step2:> Boot : Type linux rescue & press enter

Step3:> Do you want to enable the networking interface

                  yes/no  
Choose no for standalone system

Step4:> chroot /mnt/sysimage

                     continue
Press continue

Step5:> Type chroot /mnt/sysimage

Step6:>Type vi /etc/grub.conf

In grub.conf file remove the line

password --md5 ------------------------------

:wq

Step7:> exit

Step8:> reboot