Best technique to uninstall Linux

If you have only Linux (any distro) installed on your computer, the following procedure will totally wipe off Linux from your hard drive and also all the data on it.

Step 1: Boot Linux.

Step 2: Open the Terminal.

Step 3: If you are not logged in as root, log in as root.

Step 4: Type this command:
dd if=/dev/zero of=/dev/hda bs=512 count=1

Step 5: Hit Enter.

Step 6: Restart your computer.

When you restart your computer you will see that there is no OS on your hard drive. So before doing this be sure you have your other OS cd with you so that you can install that.