Password Authentication Problem

I have a Dell Laptop, Inspiron 8000. After giving it to a friend to use, the system refuse to boot up when I tried to use it. Instead of booting, it displays the following message on the screen:

THIS SYSTEM, #3T5960J-595B, IS PROTECTED BY A PASSWORD AUTHENTICATION SYSTEM. YOU CANNOT ACCESS THE DATA ON THIs COMPUTER WITHOUT THE CORRECT PASSWORD. PLEASE TYPE IN THE PRIMARY OR ADMINISTRATOR PASSWORD AND PRESS ENTER.

Pls, how do I solve this problem. It doesn’t even get to setup stage. My former password can no longer open it. I won’t mind if I can reprepare the harddisk. But how do I reach that stage.
Powell.