1. Turn your Sony PCG-GR390K laptop over.
2. Find the laptop battery release button lock for your Sony PCG-GR390K laptop.
3. Now that your Sony PCG-GR390K 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 PCG-GR390K battery is removed, grab your replacement Sony PCG-GR390K battery for installation.
6. Insert the battery into the slot. Push the Sony PCG-GR390K battery towards the laptop and secure it in place.