1. Turn your HP ZD8120ea laptop over.
2. Find the laptop battery release button lock for your HP ZD8120ea laptop.
3. Now that your HP ZD8120ea 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 HP ZD8120ea battery is removed, grab your replacement HP ZD8120ea battery for installation.
6. Insert the battery into the slot. Push the HP ZD8120ea battery towards the laptop and secure it in place.