For repairing your Grub by using LiveCD.

If your GRUB system stops in the case,

STAGE 1
STAGE 1
STAGE 1
.
.
.

, you will be able to mend broken yourselves grub with LiveCD.
First, start up computer from LiveCD.
Next, mount important partition.
Then chroot at the mount point, and type 'grub-install hd0
(or /sbin/grub-install hd0)'.

#mount /dev/hdax /mnt
#chroot /mnt
#grub-install hd0

( This is old )