If you wrote lilo to a floppy, then boot with that floppy so you can make the changes to your /lilo.conf file.
If not you will need to boot up with your first installation disk, (I'm assuming that the first installation disk is also a rescue disk.
Instead of starting the installation program, in the initial lilo boot screen enter the boot option 'rescue'. This will give you a system running on a ram disk. You can use the command 'fdisk -l' to list your partitions if you don't know them. Your next order of business is to mount your (normal) root partition somewhere like /mnt. If you have your normal /usr or /boot directories on seperate partitions you need to boot them next, underneath the just booted root partition.
( note: if the rescue system has an option to mount your system, just select that option. )
For the sake of example, suppose that the \boot directory is on its own partiton ( hda1 ), then you have a swap partition, then the root partition is on the first extended partition ( hda5 ), and these partitions use the ext2 file-system. Now you would mount the old root partitions somewhere first.
Code:
mount -t ext3 /dev/hda5 /mnt
mount -t ext3 /dev/hda1 /mnt/boot
Now you need to cd to /mnt and make this the new root directory. This is because we need to run lilo to save the changes in the MBR, and it scans for locations on the hard drive. Otherwise, when Lilo in /boot for vmlinuz it will be looking in your rescue systems /boot directory.
Code:
chroot /mnt
bash -l
The second line executes bash in the login mode so that your paths and environment get set up.
Now using 'vim', or any other console text editor, edit /etc/lilo.conf.
Make sure that the boot= entry is correct (probably should be boot=/dev/hda.
Next check the root= entry. For our example it would be /dev/hda5.
Save the lilo.conf file and execute '/sbin/lilo'.
This will save the information. If there is a problem with one of the stanzas or one of the partitions, there will be an error message, and you need to fix the problem with lilo.conf and retry running lilo.
Hopefully this will do it for you. Good luck.