Re: Reformatting a locked laptop
From what I can gather, you're pretty much stuck if you don't own a copy of a Mac OS X disc. You could try contacting Apple to see if they can help you.
To reset the password using the disc,
1. Insert the Mac OS X Install disc and restart the computer.
2. When you hear the startup tone, press and hold down the C key until you see the spinning gear.
3. In the Installer, choose Utilities > Reset Password.
4. Follow the onscreen instructions to change the password.