Internal affairs: Laptops aren't difficult to prise apart and start tinkering with, although doing so will often invalidate your warranty. Many have a variety of trapdoors and ad-hoc covers scattered over the laptop's underside, allowing you access to the upgradeable components. One of these will usually provide easy access to the hard drive.
Before removing any screws, ensure you're grounded - any static charge you generate could cause harm to the delicate electronics inside your laptop.
An electro-static discharge wrist-strap can be useful here, although it's easy enough to simply touch your finger on a grounded radiator from your seated position before starting work.
Before opening up the case, disconnect the laptop's charger lead and remove the battery pack.
Now look around for the screws that secure the bottom-plate cover above the hard drive. Remove these, taking careful note if they're different sizes. It can be useful to have a notepad to hand to keep notes of which screw came from which position. After removing the screws, place them in a small dish or saucer to make sure they don't roll off your work surface.
The existing hard disk will typically be fixed to the laptop chassis by two or four screws, often attached via a separate lightweight cradle or harness.
After removing the retaining screws, gently slide the drive away from the SATA edge connectors on one of its ends. The laptop side of these electrical connections may be soldered to the motherboard, or there may be a ribbon cable attachment.
With the old drive now free, remove the cradle if necessary and transfer this to the new SSD. Insert the new SSD drive into the laptop, ensuring the SATA edge connector is firmly seated in place.
Replace the drive hatch or laptop bottom cover and replace all securing screws.Now re-insert the battery power pack and connect the mains power supply.
If you've already cloned your OS to the SSD before exchanging drives, your system should be ready to go when you power it up. If you didn't do so earlier, you'll need to clone the backup or original drive to the SSD. And if you decided to take the longer but more thorough route, you can prepare to reinstall Windows along with the rest of your required programs and files.
If you decide to reinstall Windows, head to tinyurl.com/m9a7nb for advice.