1. Turn your Sony vpceb42fx laptop over.
2. Find the laptop battery release button lock for your Sony vpceb42fx laptop.
3. Now that your Sony vpceb42fx 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 vpceb42fx battery is removed, grab your replacement Sony vpceb42fx battery for installation.
6. Insert the battery into the slot. Push the Sony vpceb42fx battery towards the laptop and secure it in place.