If you have only one administrator account on the computer and you needs to reset your Administrator password in Mac OS X follow the steps given below. You might need to do this, for example, when someone has lost or forgotten his or her account password. Original administrator account stands for the one that was created immediately after installing Mac OS X in setup your Mac options. For resetting Admin password you need Mac OS X Install disc ( Not the recovery Disc ). Remember the Install disc should be closest to the version of Mac OS X installed
Note: The default keyboard layout is U.S. English while started from the installation disc. If you use a keyboard layout other than U.S English, use the Input menu (the flag icon on the right side of the menu bar) to select the desired layout before typing a new password.
Important: Do not select “System Administrator (root)”. This is actually the root user. You should not confuse it with a normal administrator account.