I made a fresh installation of Slackware 14 on sda2, ran through the beginner's slackware page, everything was OK. I connected an old hard drive to USB and booted it to get some files. When I rebooted into Slackware it gets past lilo then hangs and says this, regardless of what I choose at lilo. It panicked at some point, I think after I typed exit.
mount: mounting /dev/sda2 on /mnt failed: Invalid argument
ERROR: No /sbin/init found on rootdev (or not mounted). Trouble ahead.
You can try to fix it. Type 'exit' when things are done.
/bin/sh: can't access tty; job control turned off
I couldn't find a quick fix so I reinstalled 14 and repeated the process with the same result.