Using Knoppix to remove the GRUB Boot Loader password and reset the root password on Redhat

grub can be password protected so that you can't add a kernel parameter to boot to single user mode, this makes it difficult to reset the root password or pass custom parms to the kernel.

Fortunately Knoppix http:// can be used to work around these issues

Booting Knoppix

Insert CD into CDROM and reboot computer (Make sure the BIOS is configured to boot from the CD before the Hard Disk)
Boot into Knoppix
I think Knoppix will find and mount, or at least enter the current Linux hdd partitions in /etc/fstab with mount points in /mnt/hdXX, but you may have to remount the shares as rw before editing the files as below.
i.e
mount /mnt/hda2 -o remount rw

You need to know where your /boot partition and your / (root) partitions are.
Mine where /dev/hda1 and /dev/hda2 respectively and hence had mount points of /mnt/hda1 and /mnt/hda2 from within knoppix

Remove the Grub Boot Loader password option

vi /mnt/hda1/grub/menu.lst

default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
# comment the password line out
# password --md5 $1$NnuIG0$82jbm.Z46rbeoNp6t3kX2/

title Fedora Core (2.6.3james1)
        root (hd0,0)
        kernel /vmlinuz-2.6.3james1 ro root=/dev/hda2 hdc=ide-scsi rhgb
        initrd /initrd-2.6.3james1.img

Blank the root password

To blank the root password you need to remove the 2nd field from the root line in /etc/shadow
vi /mnt/hda2/etc/shadow
root line before
root:$1$rjeuJQy9$XK.83dj1kAFl9yT9w.44c1:12486:0:99999:7:::
root line after
root::12486:0:99999:7:::

Save the edit, run /sbin/shutdown -r now, (remove the knoppix cd)

Log in as root with no password and reset the password