Effectively you'll need to do a "grub-install"

If booted from a Live/Rescue CD, make sure your Linux install is mounted somewhere like /sysimage/root and that the "/boot" directory is properly mounted as well if its a separate filesystem (/sysimage/root/boot) and it has the proper files in it (kernel, initrd, /sysimage/root/boot/grub/, etc...)

do a "grub-install --help" and make sure you are using the proper arguments, but effectively you'll need to do this:

grub-install --root-directory=/sysimage/root /dev/hda

Ensuring /dev/hda is the right device according to the Live/Rescue CD. Oh one other thing get a Live/Rescue CD that has the proper version of grub on it as well... (your Linux Version installed should probably be good one to use.)

You have something going on heat related.

But, the "chaining" you are talking about doesn't pertain to MBR. Its pertains to grub once its running. Chain booting will point things properly.

As long as the MBR knows where the menu.lst is, it doesn't matter.

use which ever the "device.map" declares as hd0... in fact

grub-install hd0

from the running system should work without a problem.

Yeah, I know its scary. Try doing it remotely. :P