- Press the button to boot your computer and immediately press the C letter key until the Mac OS X installation disk starts.
- Click on Use English for the main language and click on the arrow in the bottom right corner.
- In the top menus, click on Utilities / Reset Password...
- Click on your hard drive, chose your username and then type your new password twice and click Save.
- In the top menus, click on Reset Password / Quit Reset Password.
- In the top menus, click on Mac OS X Installer / Quit Mac OS X Installer...
- Click on Restart to restart your computer.