Changing Login Password
Open System Preferences by selecting that option under the Blue Apple Menu in the upper-left corner of the screen, or clicking on the System Preferences icon located on the Dock, and click on the Accounts preference pane.
In the list of displayed accounts, select your. Click on the Password option, and tab to the password field. Enter the new password twice—first under password and again under verify. Please note: The original password you logged in with is required prior to creating a new password.
Figure I: OSX v10.3.9
Figure II & III: OSX v10.4