Instructions
Turn on your Sony PlayStation 3.
Select the "Game" menu.
Select the "Saved Data Utility" option.
Highlight the "Grand Theft Auto 4" save file and press the triangle button on your controller. Highlight "Delete" and press "X." The "Grand Theft Auto 4" save file is now deleted.
Highlight the "Grand Theft Auto 4" system file and press the triangle button. Highlight "Delete" and press "X." Your "Grand Theft Auto 4" account is now completely deleted from your PlayStation 3.