1. Turn your Sony PCG-3A3L laptop over.
2. Find the laptop battery release button lock for your Sony PCG-3A3L laptop.
3. Now that your Sony PCG-3A3L 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 PCG-3A3L battery is removed, grab your replacement Sony PCG-3A3L battery for installation.
6. Insert the battery into the slot. Push the Sony PCG-3A3L battery towards the laptop and secure it in place.