Which product key is needed for clean install of windows

Hello,
I'm in the process of backing up data and product keys for a fresh install of Windows. Upon digging on google for how to find your windows product key, I found several ways to find it. My HP has a COA sticker with a Windows 7 product key. I also used Produkey, which gave me a Windows 10 Pro key. Thirdly, I used a script found here and turned into a .vbs file which returned a product key:

How to Find Your Lost Windows or Office Product Keys

All three of these Windows keys are different. This computer was purchased with Windows 7 Home Premium, which was later upgraded to Windows 8, and has since been upgrade to Windows 10 Pro. I've read that OEM product keys are tied to the hardware and that's the one I need, but I wanted to see if anyone else had anything to say. Will I still be able to install Windows 10 Pro with the old key, and if so, any ideas as to why the others are different?

Now that you're on Win10 Pro, you don't need a key. You can reinstall (even a clean install) and windows will activate without a key. It's now called a "Digital License" and is tied to your computer based on a mysterious mix of component IDs held in Microsoft's activation servers. It may also be tied to your Microsoft Account if you're using one.

Microsoft Account - Link to Digital License on Windows 10 PC

Indiana JD said:

This computer was purchased with Windows 7 Home Premium, which was later upgraded to Windows 8, and has since been upgrade to Windows 10 Pro.

At which step did you change from Home to Pro?

Look at Settings > Update & security > Activation. If it says 'activated with a digital licence' you can do a clean install without providing a key (click 'don't have one' or 'skip' if asked). The clean install should activate as soon as it can contact Microsoft's activation servers.

Bree said:

At which step did you change from Home to Pro?

Look at Settings > Update & security > Activation. If it says 'activated with a digital licence' you can do a clean install without providing a key (click 'don't have one' or 'skip' if asked). The clean install should activate as soon as it can contact Microsoft's activation servers.

I'm honestly not sure how it got to be a Pro license. It has been long enough now since upgrading to 8 that I might have upgraded to something that was the Windows 8 equivalent to Windows 10 Pro. Nevertheless, the COA sticker says Windows 7 Home Premium and the Edition under Settings > Update & Security > Activation now says Windows 10 Pro. It does also say that "Windows is activated with a digital license linked to your Microsoft account."

I suppose I will have to do the clean install, and upon signing in to the Microsoft account at the login page Windows 10 Pro will be activated? Also, there are a couple of Microsoft accounts used as logins on this computer. I'm nearly certain I know which one the activation is linked to, but is there a quick easy way to tell for certain?

You don't need a Microsoft Account at all. It will retrieve the digital license stored on Microsoft Activation servers based upon the digital unique ID of the COMPUTER, not the Microsoft Account.

Fafhrd said:

By way of explanation:

When Windows 8 came out on 26 October 2012, there was a £/$15.00 offer that upgraded any recently (~6 mo) purchased Windows 7 OEM edition to 8.0 Pro Retail. Quite a good deal at the time. And a free upgrade to MCE Pro followed, both obtained by contacting Microsoft, who used 3rd party partners to handle sales, and email product keys to applicants.

Both the 8 Pro and the 8 MCE Pro product keys given out with these offers are valid upgrade keys for Windows 10 Pro.

And £25/(was it $40 in the USA?) got you/me a Windows 8 pro upgrade from Windows XP as well, which also applied to Vista and any Windows 7 machines which were too old for the £15 offer. £25 well spent!