Once you have Windows up and running you might also want to take a look at our guide to the 10 Best new features in Windows 10.
How to check if Windows 10 is activated
The chances are Windows 10 is already activated on your system, as the product key is requested during the installation procedure. To check this on your PC press the Windows key then select Settings> Update & Security> Activation. In the main panel you’ll see details about the version of Windows you’re running, and whether it’s active or not. If the message reads Windows is activated then you don’t need to do anything at all.
How to activate Windows 10 with a Windows 7, 8, or 8.1 product key
If you’ve taken the free upgrade to Windows 10 that Microsoft has been offering since the release of the OS, then you’ll automatically be activated via the digital entitlement route. This basically means that Windows 10 recognised the previous version on Windows that was on the PC when you did the upgrade and transferred the validation from that version to this.
If you ever experience any problems with the activation, then all you need to do is follow the instructions from the ‘in brief’ section above and use the product key from Windows 7, 8, or 8.1 that came with your machine (usually on the label found on the bottom of your laptop, or in the documents that came with your desktop).
Note: We’re told by Microsoft that this method will still work after 29 July 2016 when the free upgrade offer is due to end.
Activating Windows 10 with a purchased product key
If you purchased a boxed copy of Windows 10 from a retailer, then you’ll find the product key on a label inside the box. When you put the disk into your machine and run the installation, at some point in the process you’ll be asked for the product key. Enter the code and your copy of Windows 10 will then be automatically activated once you connect to the internet.
Digital versions of Windows 10 behave in exactly the same way, except the product key is usually included in the confirmation email that you would have received when you purchased the OS.
Those who bought a new PC with Windows 10 installed should also find that it’s already activated. Your product key will be in the packaging, most likely on a card that came with the PC.
If you ever find that your version of Windows says it isn’t activated then use the tried and trusted method of pressing the Windows key, then selecting Settings> Update & Security > Activation, clicking Change Product Key, then entering the 25 character product key you have on your documentation or email.
Martyn has been involved with tech ever since the arrival of his ZX Spectrum back in the early 80s. He covers iOS, Android, Windows and macOS, writing tutorials, buying guides and reviews for Macworld and its sister site Tech Advisor.