Remove grub password
Remove grub password allowing you to edit grub lines.
1. Boot vm from Red Hat or Centos cd
2. Select "Troubleshooting" from the menu
3. Select the "Rescue" option from the menu
4. Select "Continue" from the menu, this will mount the os to /mnt/sysimage
5. Depending on what distro you are running you need to edit one of these files:
/mnt/sysimage/boot/grub/menu.lst /boot/grub/menu.lst /etc/grub.conf /boot/grub/grub.conf
7. Completely remove the line that starts with "Password", you can do this by moving to the line and pressing "dd"
password --md5 $hgUjKUFhedfa$0947$hFgrjdjskwkel34dGhyTreefgj.nGr4Y..
8. Save and exit using:
You should now be able to press "e" at the grub menu to edit the boot lines without being prompted for a password.