Admin password reset

[hoggyjay]

Hi all,
I bought a second hand iMac 2009 with High Serria installed. The previous owner thought he had done everything to clean the hard drive and start freash.
It would appear that I’ve only have a user password. When trying to add printers etc I am asked to enter the admin password.
I have contacted the previous owner who has done his best to supply the correct details but still the problem arises.
Is there away to completely start again and set up my own admin account?

Thanks in advance.

 

[Lufbrarunner]

• Reboot your Mac while holding down the Command key and R. Keep holding the key combination until the loading bar appears.
• Once in the Recovery Mode, select Terminal from the Utilities menu.
  • If things just got a bit too geeky for you, don’t be alarmed. If you follow the next few steps, you’ll recover your lost admin password in no time.
• Type “resetpassword” in the Terminal window and hit enter.
• A welcoming graphical window will appear, allowing you to reset your admin password in a familiar way.
• Select the storage device that contains the operating system.
• Select the admin account.
• Click on the Change Password button.
• Enter a new password as well as a new password hint.
• Save and restart from the main menu.
• Log in with your new admin password.