1. Turn your Dell E5400 laptop over.
2. Find the laptop battery release button lock for your Dell E5400 laptop.
3. Now that your Dell E5400 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 Dell E5400 battery is removed, grab your replacement Dell E5400 battery for installation.
6. Insert the battery into the slot. Push the Dell E5400 battery towards the laptop and secure it in place.