Just boot from a live-disk, if it doesn't have grub, chroot into the linux on hda and call grub from there. Otherwise just use the grub that's on the liveCD.
bash$ grub
grub> root(hd0,0) <-- This is where your BOOT directory structure resides, if for example /boot is mounted on /dev/hda2, use (hd0,1), otherwise use the partition where / is.
grub> setup(hd0)
grub> quit
Sorted. Grub has built in help and TAB-autocomplete, so if you're not sure which partition is which, you can use this to get around. |