1. Turn your Sony VGN-FW390Y laptop over.
2. Find the laptop battery release button lock for your Sony VGN-FW390Y laptop.
3. Now that your Sony VGN-FW390Y 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-FW390Y battery is removed, grab your replacement Sony VGN-FW390Y battery for installation.
6. Insert the battery into the slot. Push the Sony VGN-FW390Y battery towards the laptop and secure it in place.