Instructions
Power on your PlayStation 3, and then sign in to your account.
Use the left and right arrows on your controller to scroll to the "PlayStation Network" menu.
Scroll up to the "Account Management" option, and then press "X" to select it.
Scroll down to "System Activation," and then press "X" to select it.
Press "X" to select the "PS3 System" option, and then press "X" to select "Game."
Highlight the "Deactivate System" option, and then press "X" to select it and deactivate the console from game sharing.
Press the "Circle" button twice, and then scroll to the "Users" menu.
Select your account, and then press the "Triangle" button.
Scroll to "Delete," and then press "X" to select it.
Select "Yes," and then press "X" to delete the account.