Alternatively. go to
www.bootdisk.com and d/l the file needed to make a W98se boot disk. Create the floppy, set your floppy drive as the first boot device in BIOS, and then issue the command FDISK... at the menu, elect to delete the hard drive's partition.
Another option is the freeware program "Killdisk" (
www.killdisk.com) which will zero-write the hard drive, returning it to the condition it was in when it left the hard drive manufacturer.