What do you need to do to use a command-line interface?

To get to the command line on your computer click on the Start button, click on Run, then type "cmd" in the run box. You will go to a black box called DOS. You will also see the command line prompt C:>, this is where you type in DOS commands. You can use DOS commands to do just about anything you can do in Windows except it's more work, you can copy, move, del files, etc. To get out of DOS just type Exit at the command prompt. You need to find yourself a book on DOS commands to know how to work it.