Why not keep your operating system on the original drive - 40 GB should be more than enough - and simply move your data onto the new 120 GB drive. You don`t need the heartache of transferring the OS - do you?
Samsung Galaxy A9 review: Hands-on
Can the Huawei P20 Pro really replace a digital SLR?
Surface Laptop 2 vs MacBook Pro
Samsung Galaxy S9 vs Sony Xperia XZ3