1. Turn your Acer 4240 laptop over.
2. Find the laptop battery release button lock for your Acer 4240 laptop.
3. Now that your Acer 4240 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 Acer 4240 battery is removed, grab your replacement Acer 4240 battery for installation.
6. Insert the battery into the slot. Push the Acer 4240 battery towards the laptop and secure it in place.