PHYSICAL INSTALLATION
Installing a new hard disk is normally easy, but the specifics vary from case to case. Simplest of all is an M.2 drive: simply push your drive into the slot, and screw the retaining screw at the opposite end into place. M.2 drives are notched, so you physically can’t insert them the wrong way around.
To install a 3.5in SATA hard disk in a desktop, you’ll need to connect it to the motherboard using a 7-pin SATA data cable; these cables are reversible, and the plugs are L-shaped, so again it’s very hard to get wrong. If you’re replacing an older disk, it’s a good idea to connect the new one to the same SATA port on the motherboard. Steer clear of legacy SATA 2 ports, though, as these are only capable of half the speed of regular sockets.
You’ll also need to plug a 15-pin SATA power connector into the drive: your PC’s internal power supply should provide one of these. If not, a few pounds will buy you an adaptor that will let you use the drive with an older four-pin Molex power connector. Once you’ve got both cables hooked up, slide the drive into an available bay in your desktop case and screw it firmly into place from both sides.
With a 2.5in SATA SSD, the procedure depends on what you’re putting it into. For a desktop system, it’s exactly the same as above. The only difference might be that if your case doesn’t have a dedicated 2.5in bay, you’ll need an adaptor to make it fit it into a 3.5in bay. Or, you can just screw it into one side of a 3.5in bay and leave it hanging – this should be secure enough, as long as you don’t regularly move your PC around.
On a laptop, the hard disk is normally held in place by a custom mounting: unscrew this, then pull the drive carefully away from the SATA data and power connectors to disconnect it. Then, attach the mount to your new drive; if the new disk is thinner than the old one, you might also need to affix plastic or foam spacers – these are often provided with the drive. Finally, drop the new disk into the drive cavity, push it firmly onto the SATA contacts and screw it into place.