Glad you got this figured out. As a long-time Slacker I have used this trick for years. I posted it to this list quite a while ago, but it is no doubt buried somewhere in the bowels of this archive, never to be seen again. One point -- This only works with LILO, not with GRUB, which is one of the many reasons I prefer LILO. As more distributions start using GRUB (Why?? Kanotix, Mepis -- are you listening? Is it only for the prettier splash screens?) this trick becomes less and less useful.

As baldyeti already said, it works best to use the CD you used for the HD install.