[Jeordiewhite]

http://dban.sourceforge.net/
Theres a free program for doing so. You go to Darik's Boot and Nuke 1.0.7 and download the dban-1.0.7_i386.exe and this will prompt you to put in a floppy disk or you may download the iso and burn it to a cd if your able to do so.
Once if finishes creating the floppy, you reboot and either go into your bios pressing f1 or delete key and change it to boot to floppy or hopefully it's set to boot from the floppy already.
Then you should be able to do as what you intend to do.