1. Turn your HP zt3115EA laptop over.
2. Find the laptop battery release button lock for your HP zt3115EA laptop.
3. Now that your HP zt3115EA 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 zt3115EA battery is removed, grab your replacement HP zt3115EA battery for installation.
6. Insert the battery into the slot. Push the HP zt3115EA battery towards the laptop and secure it in place.