1. Turn your Compaq 2125AD laptop over.
2. Find the laptop battery release button lock for your Compaq 2125AD laptop.
3. Now that your Compaq 2125AD 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 2125AD battery is removed, grab your replacement Compaq 2125AD battery for installation.
6. Insert the battery into the slot. Push the Compaq 2125AD battery towards the laptop and secure it in place.