1. Turn your HP ZD8105ca laptop over.
2. Find the laptop battery release button lock for your HP ZD8105ca laptop.
3. Now that your HP ZD8105ca 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 ZD8105ca battery is removed, grab your replacement HP ZD8105ca battery for installation.
6. Insert the battery into the slot. Push the HP ZD8105ca battery towards the laptop and secure it in place.