Enter a Windows key during setup, or under Settings, System, Activation, Change product key. Each software page states its edition, region and conditions.
A Windows key is entered during Windows setup, or afterwards in Windows settings. An Office key is entered on Microsoft's setup site or in the way the product's Activation details tab describes. Buy the edition you have installed or will install: a key for one edition does not activate another.
01Check before buying
- 1On the Games list, open All filters and choose Software under Product type to see software keys.
- 2Read the product name for the exact edition and version, for example Home or Professional.
- 3Check Region, and the Can be activated in line in the purchase panel.
- 4Read the Activation details tab for conditions specific to that key.
02Activate Windows
These steps follow Microsoft's help page "Activate Windows".
- 1If you are installing Windows, enter the key when setup asks for a product key.
- 2If Windows is already installed, select the Start button, then Settings, System, Activation.
- 3Select Change product key.
- 4Enter the 25-character key and follow the instructions.
If Windows shows an activation error, write down the error code.
03Activate Office
Microsoft's help says a new, unused Office or Microsoft 365 product key is entered at microsoft365.com/setup, signed in with the Microsoft account that should own it. Some products are activated another way. If the product's Activation details tab, or Show details on your order page, gives different steps, follow those.
04If that did not work
- Windows or Office shows an error code: take a screenshot that includes the code. Do not keep re-entering the key.
- The key is for a different edition: it cannot activate your installation. See I bought the wrong product or region. Can I get a refund? for what the Refund Policy says.
- The key is rejected as invalid or already used: copy it again from the order page, then see My game key is not working or was already used. That article also covers software keys.