Ah, the mysteries of Grub.......

You can probably find what you need with a Google.

But are you sure you don't have Lilo?

try

lilo -v

from a terminal as an ordinary user. If you get output like:

LILO version 22.5.9, Copyright (C) 1992-1998 Werner Almesberger
Development beyond version 21 Copyright (C) 1999-2004 John Coffman
Released 08-Apr-2004, and compiled at 15:30:00 on Aug 15 2004
Debian GNU/Linux

/etc/lilo.conf: Permission denied

then you have Lilo.

Just su to root and do:

/sbin/lilo

and you should find you have it on your mbr.

Failing that, post the error message. Some versions seem to have one line in /etc/lilo.conf which needs #ing out.