1. Turn your Sony VGN-CS118E laptop over.
2. Find the laptop battery release button lock for your Sony VGN-CS118E laptop.
3. Now that your Sony VGN-CS118E 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 Sony VGN-CS118E battery is removed, grab your replacement Sony VGN-CS118E battery for installation.
6. Insert the battery into the slot. Push the Sony VGN-CS118E battery towards the laptop and secure it in place.