Every Windows Key is associated with a particular version. If you are getting Activation Error 0xC004F034 during activation of Windows, it means that you entered an invalid product key or a product key for a different version of Windows.

In case you have bought the key or it came with a computer, verify it. You can connect with Microsoft support as well to further to validate it. If the key is correct, then you need to check which version it belongs to. Download the correct version, and then use this key.

Lastly, this code is also associated with the Key Management Service (KMS) server. In case your Windows installed on a device that connects to a Key Management Service (KMS) server, contact your organization's support person for more info about how to activate Windows.