Between you guys, a post from another forum, and some experimenting I've gotten it to boot again!
For anyone else that has this problem this is what I did.
I made a Linux boot disk on another working system:
(if necessary unmount the floppy: umount /dev/fdo)
mkbootdisk 2.4.21-0.13mdk (the numbers correspond to your kernel version, I found the correct version number in /lib/modules)
Boot the problem system with the boot floppy. Once you have booted, go into the terminal as root or use the "super user" terminal and run: /sbin/lilo
That's it!! You should be able to boot from your hard drive again!
Thanks again everyone for your help!