Some good news for you. It looks to me like your laptop has 2 slots for ram ... one of which is empty, the other has a 8 Gb stick ... hence, all you need is 1 8 Gb ram stick. In my experience, this is unusual ... they almost always come with 2 4 Gb sticks and then to upgrade to 16 Gb you need to buy 2 8 Gb sticks. Lucky you!