1. Turn your Sony VGN-NS255J laptop over.
2. Find the laptop battery release button lock for your Sony VGN-NS255J laptop.
3. Now that your Sony VGN-NS255J laptop battery is unlocked, find the battery release button down.
4. Holding the laptop battery release button, gently pull your battery away from the laptop.
5. Now that your Sony VGN-NS255J battery is removed, grab your replacement Sony VGN-NS255J battery for installation.
6. Insert the battery into the slot. Push the Sony VGN-NS255J battery towards the laptop and secure it in place.