If you've purchased a copy of Windows 8.1 Pro, you can find the product key in the following places:

If you've lost your product key, don't worry. You can still retrieve it using third-party software or by contacting Microsoft support.

Press Windows Key + X > Command Prompt (Admin) > type wmic path softwarelicensingservice get OA3xOriginalProductKey . 2. How to Activate Windows 8.1 Pro 64-bit Once you have your key, follow these steps to activate: Microsoft Community Hubhttps://techcommunity.microsoft.com

A Windows 8.1 Pro product key is a 25-character code used to activate a copy of Windows 8.1 Pro. The product key is required to unlock the full features of the operating system and to verify that your copy of Windows is genuine. Without a valid product key, you may be limited to a trial version of Windows 8.1 Pro, which will expire after a certain period.