How to change Mac admin password without disk

[techanita]

Unfortunately i had lost my disk and had also forgotten my admin password. I'm trying to change my Mac admin password, but with out disk i'm unable to do so. So, can any body tell me that how to change Mac admin password without disk? Any one have any idea about it? Please provide me the correct information on the above issue. Any kind of information on the above issue would be appreciated. Thanks in advance.

[Devasis]

According to me you need to enter terminal and create a new admin account. There are hidden administrator account from where you can log on it and you can change or remove all the other passes of your computer without knowing the previous passes.

[Solomon]

CMD+S on boot does not work due to open firmware. Just type ctrl alt del twice and then type Administrator on the account name and you can enter. The Safe Mode Welcome screen might display some of the other users on your system. If that won't work, restart the computer and toggle the F5 button.You will get screen that will ask you if you want to boot with command prompt, choose it and then type net user, then press enter.

[MrChris-]

Boot up your computer while holding Apple + S - this will take you into single user mode. To Avoid these types of hack remember to block single user mode by setting a firmware password and don’t forget the password. At the prompt, type: /sbin/mount -uw / Then, type: passwordd username (where username is the name of the account for which you want to set the password) For more information, you can check out the following link.