Windows 10 Clean Install and Windows 8.1 Product Key [duplicate]

I'm doing a Windows 10 clean install on a machine that already has Windows 8 on it, and still have my Windows 8.1 disk and product key. Will this work for a product key for Windows 10?

You need to perform an in-place upgrade from Windows 8 to Windows 10. The Windows 8 key will not work on Windows 10 as a new key is recorded in cloud tied to your MS ID and the machine's ID (even if the machine is a VM). Further details can be found here: http://blogs.technet.com/b/canitpro/archive/2015/08/13/step-by-step-how-to-clean-install-windows-10-without-formatting-the-drive.aspx

If you have already updated that computer to Windows 10, you will not need a product key at all. You will be able to choose "Skip" at the point where it prompts for a product key. The reason it still prompts you for a product key here is if this is really a new install, you have moved that license to a different machine, or if you are changing editions of Windows. If you have already activated the same edition of Windows 10 on this computer, just choose "Skip".

If you have not yet updated that computer to Windows 10, you must first install and activate Windows 7, 8, or 8.1. Then you will be able to upgrade the installation to Windows 10 through July 28, 2016.