Do you intend to install any other operating system on the laptop?
If yes then usually the the installation routine for the other operating system will offer you the choice to use the whole disk, if this option is selected then the existing hard drive is formatted before this installation, effectively removing XP from the laptop.
If no then you can look at creating a bootable disk or CD, if you google for repair CD's / Disks you should find plenty listed. Once you have created your bootable CD / disk then boot into this. One that I have used in the past is DBAN, fairly straight forward just pop the CD in boot to the CD follow the instructions.
If you cannot boot from CD but can boot from floppy then google for a bootable floppy, most of them will have utilities for creating disk partitions and formatting the hard drive.
Hope this helps