1. Turn your Compaq 2155AE laptop over.
2. Find the laptop battery release button lock for your Compaq 2155AE laptop.
3. Now that your Compaq 2155AE 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 Compaq 2155AE battery is removed, grab your replacement Compaq 2155AE battery for installation.
6. Insert the battery into the slot. Push the Compaq 2155AE battery towards the laptop and secure it in place.