Be aware of the fact, that in order to start-up at boot time, linux needs a bootloader: lilo or grub, perhaps there exist others, even if linux is the only OS on the harddisk.
So you choose for the Slackware default lilo.
I assume you have made a boot-floppy at installation time, with which you can startup your slackware.
there must be a file /etc/liloconf
If you don't have it, you can make one (as superuser) very simple with the aid of
# /sbin/liloconfig
You will get the screens for installing lilo, that you remember from the slackware installation.
In your case (only one OS on the computer) you choose for the simplest option.
if you don't have liloconfig it is time to re-install lilo.
startup your internet browser, go to
www.slackware.com and on 'packages'.
and look for lilo.
This gives you the correct package-name to re-install.
If you don't have a bootfloppy, things can be done on a more difficult way (with a live cd and the program chroot), ask here if needed.
Hope this helps, ask again if you have troubles.
succes.
