I would suggest booting from a cd to linux rescue(redhat)
or booting from a floppy and chroot ' ing to your linux partition, and rerun /sbin/lilo.
it could be that simple.
Norton erased the MBR loader aye? DAMN! what a bastard.
learn about chroot from www.google.com
then boot, mount your partitions, chroot, and /sbin/lilo, reboot.