Mac OS X 10.5 Help
If you forget your administrator password
If you don’t remember your administrator password, you can reset the administrator password using the Mac OS X Install disc.
Important: Because a user with the Mac OS X Install disc can gain unrestricted access to your computer, you should keep the disc in a safe place.
To reset the administrator password using the Mac OS X disc:
Insert the Mac OS X Install disc and restart the computer.
When you hear the startup tone, press and hold down the C key until you see the spinning gear.
When the Language Chooser appears, select your language and click Continue.
Choose Utilities > Reset Password.
Follow the onscreen instructions to change the password.
Quit the Installer and restart your computer while holding down the mouse button to eject the disc.
You can change your login keychain password in Keychain Access to match your new account password to unlock your keychain when you log in.