1. Turn your HP DV4040CA laptop over.
2. Find the laptop battery release button lock for your HP DV4040CA laptop.
3. Now that your HP DV4040CA 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 DV4040CA battery is removed, grab your replacement HP DV4040CA battery for installation.
6. Insert the battery into the slot. Push the HP DV4040CA battery towards the laptop and secure it in place.