I don't know if I can help, but I suppose we need some more info.
You have a live Linux and are able to run a Terminal / Konsole?
The output of
l like list
and / or
could be helpful.
I don't know much about slackware (test some years ago) and LILO.
But normally - if you install Grub - you install the boot loader into the MBR (e.g. /dev/sda),
not in a partition, e.g. /dev/sda1 or sda2 or... (except you have a multiboot with several Linux distributions).
I installed many multiboot, always after having created partitions with GParted; I use PartedMagic live,
which is more than an OS, you have access to all files, to internet, Gparted and many useful tools.