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 File:Troubleshooting.jpg
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:
/grub/menu.lst /boot/grub/menu.lst /etc/grub.conf /boot/grub/grub.conf
6. type:
vi menu.lst
7. Completely remove the line that starts with "Password", you can do this by moving to the line and pressing "dd"
8. Save and exit using:
:wq!
9. Reboot
You should now be able to press "e" at the grub menu to edit the boot lines without being prompted for a password.