One of the reasons your PlayStation 4 Slim might not be booting is a failing hard drive. Alternatively, you may just be looking to replace it for an upgrade to either have more storage, or utilize a solid state drive to improve load times and speeds.
In this video, I will show you how to replace your PlayStation 4 Slim hard drive with a fast SSD. You only need a new drive and a screwdriver and a few USB drives to transfer your data.