1. Turn your Sony VGN-FS645PH laptop over.
2. Find the laptop battery release button lock for your Sony VGN-FS645PH laptop.
3. Now that your Sony VGN-FS645PH 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-FS645PH battery is removed, grab your replacement Sony VGN-FS645PH battery for installation.
6. Insert the battery into the slot. Push the Sony VGN-FS645PH battery towards the laptop and secure it in place.