I'm not very familiar with older versions of mac os x but I have had experience with 10.3...Does the mac have a master password set? usually after a couple tries at the admin passwd it will ask you to enter the master password to reset the admin passwd....or.....login as a network admin and change the password or you could use "single-user-boot" using command + s keys at boot up......hopfully that helps...but if it doesn't please be more descriptive of your problem