1) install Lilo on your Superblock
2) configure Lilo
3) run lilo to update the bootsector based on your config
4) execute "dd if=<linux root partition (ex: /dev/hda2)> of=bootsect.lnx bs=512 count=1"
5) copy bootsect.lnx to your winxp / win2k boot drive (ex: C:\bootsect.lnx) (you may need a floppy disk to transfer the file)
6) edit boot.ini and add the line C:\bootsect.lnx="Slackware Linux"
7) Reboot
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to remove Linux if you are using the above, simply delete the line you added and delete Linux partitions.