Putting a new hard drive or SSD into a laptop may seem like an impossibly complicated task, but it's actually very simple. Find the existing hard drive, pop it out, stick the new one in.

There are, of course, important factors to consider: what interface does your laptop use? What data from your old hard drive do you require, and how are you going to dispose of it? We've addressed these and other points in our simple, step-by-step guide to changing your laptop's hard drive or SSD.

1. Prepare, and back up. Before you do anything physical, do some research. What interface does your laptop use to connect to its existing hard drive? It's unlikely that your PC will have multiple interfaces, and if you have an older laptop with an IDE interface, you can't fit a SATA hard drive. Virtually all modern laptops ship with SATA drives, but if you're upgrading it may well be an older device.

Unfortunately, there's no simple way of finding out what kind of interface your laptop employs. Some manufacturers, including Dell, publish such details on their websites, so you can do a bit of web research to find out. In most cases, however, you'll have to take a look at the drive itself, which we'll come to in step two.

A SATA connector looks like this:

SATA interface

An IDE connector looks like this:

EIDE interface

Finally, before you start, make sure you back up the contents of you existing hard drive. And if you are intending to dump or pass on the older drive, use a data-scrubbing utility to make sure none of your information is compromised.

And remember that your PC's hard drive holds its operating system, so you'll need to install it anew on the fresh hard drive. So before you do anything else, make sure you have either your OS discs or a download copy, and the product key to validate it.

2. Get under the cover. Now you're ready to get your hands dirty, make sure you're in a clean, dust-free environment. Take precautions to remove any static, ideally by wearing an antistatic wrist band. Boot down and unplug the laptop, then remove the battery. You have to find where the hard drive is stored. There are various places for this, although generally manufacturers place the hard drive beneath a screwed-in plate on the underside of the laptop. Here are three examples:

This Toshiba laptop is an example of the way most laptop hard drives will be stored. The hard drive is on the underside, accessed via a panel which slips off sideways once two screws have been undone.

Toshiba laptop hard drive casing

The SATA interface is conected by a series of wires.

Toshiba laptop hard drive SATA connection

Our Asus Eee PC has an SSD, which is stored beneath a screwed-in panel on the underside. One of the screws was hidden under a sticker.

Asus Eee PC cover

Due to size constraints getting access to the drive will be tricky.

Asus Eee PC SSD drives

This Lenovo ThinkPad also has an SSD, in this case slotted into a screw-free, accessible slot on the back left of the device. This is about as easy as it gets.

Lenovo laptop side-loading bay

Once you've found where the old hard drive is, simply unscrew and/or unclip it, and remove it.

3. Out with the old, slot in the new drive. There are two critical parts of this procedure: the most important factor is to ensure the drive's connnectors are correctly hooked up to the interface. It's also important to make sure any screws are tight - finger tight - but not too tight. When you've attached and secured the drive, reattach any external covers.

4. Get started again. Now restart your laptop, and enter your system's BIOS. If the new hard drive is installed properly, you will see it in the BIOS, and the hardware installation is complete. (Booting into the BIOS usually involves hitting a key during the boot process, and details should be in your system's manual. If you don't have the manual, try a web search to get the heart of the problem, and if all else fails, keep rebooting and trying various likely keys such as Esc, the Function keys and so on.)  If you're struggling to find the BIOS, don't worry. During step 5 your OS will ask where it should install itself: if it suggests your newly installed hard drive, you know it's okay.

5. Operator, operator. Load your operating system disk into the computer. If you're doing it from the original disc, you simply need to follow the instructions on the screen to format and install your operating system. Once the OS is up and running, you can transfer back all the data you backed up at the beginning, and put the kettle on. Your work here is done.