If you know what you're doing, then...
Boot from your Mandy install CD 1 and go into rescue mode (press F1 and then type rescue
), and re-install your bootloader. Two methods. You can 're-install bootloader' or, the method I prefer is to 'mount partitions under /mnt' followed by 'console mode', type 'chroot /mnt' then 'emacs /etc/lilo.conf' make changes and save, then '/sbin/lilo'. Your choice
If you're unsure, then just use the 're-install bootloader' option. It should work OK.