Boot up knoppix CD
log in as superuser (needs it for admin privilege to alter system settings)
make a temporary directory in /mnt, say call it /mnt/hda9
mount your distressed knoppix in (hd0,8) which I assume to be known as hda9 in Linux. Grub counts from 0 so (hd0,8) should corresponds to hda9 in Linux.
change root to hda9, so that you are inside the distressed Knoppix
restore Grub back into the MBR of your hard disk hda
exit and reboot
The complete commands after booting up Knoppix CD are
mount /dev/hda9 /mnt/hda9
if you have a Sata disk then change every "hda" to "sda".