How to Remove an Administrator Password on a Mac
- 1). Insert the Mac OS X installation CD or DVD into the disc drive.
- 2). Restart the computer.
- 3). Hold in the "C" key immediately after the Mac startup sound comes on to boot from the disc.
- 4). Click the desired display language, then click the "Next" button.
- 5). Click the "Utilities" menu.
- 6). Click "Reset password."
- 7). Click the Apple computer's internal hard drive.
- 8). Click the administrative account from which you want to remove the password.
- 9). Leave the password boxes clear and click the "Save" button to remove the password.
- 10
Click "OK" and restart the computer.
Source...