1. Turn your Gateway NV40 laptop over.
2. Find the laptop battery release button lock for your Gateway NV40 laptop.
3. Now that your Gateway NV40 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 Gateway NV40 battery is removed, grab your replacement Gateway NV40 battery for installation.
6. Insert the battery into the slot. Push the Gateway NV40 battery towards the laptop and secure it in place.