boot with the Slackware disk and use cfdisk instead of fdisk. If your not concered with any of the data on the disk don't worry about creating dos partitions.
just use cfdisk and remove all partitions and create a Linux partition (primary) and a Linux swap partition (logical). Give the Linux primary partition the boot option. Make the swap partition double the size of your ram (unless you got a G+ of ram). That's a good start for noobies
That's what i did when i first started.