1. Turn your Compaq 2503AT laptop over.
2. Find the laptop battery release button lock for your Compaq 2503AT laptop.
3. Now that your Compaq 2503AT 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 2503AT battery is removed, grab your replacement Compaq 2503AT battery for installation.
6. Insert the battery into the slot. Push the Compaq 2503AT battery towards the laptop and secure it in place.