1. Turn your Toshiba PSL40U laptop over.
2. Find the laptop battery release button lock for your Toshiba PSL40U laptop.
3. Now that your Toshiba PSL40U 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 PSL40U battery is removed, grab your replacement Toshiba PSL40U battery for installation.
6. Insert the battery into the slot. Push the Toshiba PSL40U battery towards the laptop and secure it in place.