Need to reinstall grub

[Art Alexion]

Grub was installed on my MBR on hda.  It seems that hda has given up the 
ghost.  Not much lost (win98 that came with computer), but now I can't 
boot (currently running knoppix).  Boot is a continuous loop from the 
mem test to going through the BIOS-defined boot drives, then back to the 
mem test.

How can I get the computer to boot from hdb (where linux, the kernel, 
and the grub program are located).  To be more precise, I don't really 
understand where the grub program is located, but I think most of it is 
in /boot/grub on /dev/hdb2.

If anyone can walk me through this using knoppix, that would be 
wonderful.  I have the Knoppix 2.6.9 kernel loaded.  The Ubuntu kernel 
on /dev/hdb2 is a 2.6.8-1 kernel.