Ps3 was owned by someone else and they put a block for mature games how do you get the block off

Just restore to default setting that will erase the password they have on it, instructions are as followed. To Restore Default Settings :

1. From the XMB home menu, go to alt="Settings icon"> (Settings) > alt="System Settings icon">(System Settings) > [Restore Default Settings].
   

   alt="Restore Default settings screenshot 1">
   

2. Once you select [Restore Default Settings], you will see a list of settings that will be restored. Scroll through them and press the alt="X button icon"> button to restore the settings.
   

   alt="Restore Default settings screenshot 2">
   

3. After the operation is complete, you will see the initial setup screen that appeared the first time you turned on the PS3. You will need to go through the initial set up process before you can use the PS3.

IMPORTANT

The Restore Default Settings feature will erase any previously saved settings and restore all of the following settings to the default:

• Game Settings
• Video Settings
• Music Settings
• Chat Settings
• System Settings

  This includes terms added using alt="Settings icon"> (Settings) > alt="System Settings icon">(System Settings) > [Add/Edit Term], or predictive terms "learned" by the on-screen keyboard.
  

• Theme Settings

  This includes the information about the image set as wallpaper under alt="Photo icon"> (Photo). Also, theme, color, background and font settings under alt="Settings icon"> (Settings) > alt="Theme Settings icon">(Theme Settings).
  

• Date and Time Settings
• Power Save Settings
• Printer Settings
• Accessory Settings

  This includes keyboard or mouse settings under alt="Settings icon">(Settings) > alt="Accessory Settings icon"> (Accessory Settings). Also, Voice changer settings under alt="Settings icon"> (Settings) > alt="Accessory Settings icon"> (Accessory Settings) > [Voice Changer].
  

• Display Settings
• Sound Settings
• Security Settings
• Remote Play Settings
• Network Settings
• Internet Browser Settings

  This includes bookmarks, history, and settings added under alt="Internet Browser icon"> (Internet Browser).
  

• PlayStation®Network log in information

  This will remove the PlayStation Network sign-in ID and password for the user who is currently logged in.
  

Also, do not confuse [Restore Default Settings] with the [Restore PS3 System] option (the next option down on the menu). The [Restore PS3 System] will not only restore the default settings, but it will also delete all hard disk content. (You will lose all saved content from your PS3 system's hard drive if you use [Restore PS3 System].)

Unless you know the password they used you would need to completely re-initialize the unit as it was a new one, from the beginning, to wipe it out completely and set it back to factory defaults (sledge-hammer reset).

There is no way I know of to retrieve this lost password if you do not also know the owner's PSN information, which I'm sure you cannot get to. You might Google the question.