1. Turn your Compaq CQ50-139NR laptop over.
2. Find the laptop battery release button lock for your Compaq CQ50-139NR laptop.
3. Now that your Compaq CQ50-139NR 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 CQ50-139NR battery is removed, grab your replacement Compaq CQ50-139NR battery for installation.
6. Insert the battery into the slot. Push the Compaq CQ50-139NR battery towards the laptop and secure it in place.