1. Turn your Toshiba L40-17S laptop over.
2. Find the laptop battery release button lock for your Toshiba L40-17S laptop.
3. Now that your Toshiba L40-17S 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 Toshiba L40-17S battery is removed, grab your replacement Toshiba L40-17S battery for installation.
6. Insert the battery into the slot. Push the Toshiba L40-17S battery towards the laptop and secure it in place.