Windows 10: Product activation key

Hi There,I have recently purchased an old PC workstation from my office thru auction. It has a product key sticker of windows 7 pro OA.I have mistakenly installed the windows 10 home without activation/product key. When I tried to upgrade to windows 10pro thru Microsoft store it asked to enter product key appears an error message as shown below, My question is, did anyone else is already using this product key?If yes, How I can retrieve my key? since I'm owning the PC nowWhat can I do next? Kindly help me on this.

:)

 

Activate windows 10 after re-installing (I have lost my product key)

I own a Lenovo T430 laptop. In 2017, I installed Windows 10 using my original Windows 7 product key. Unfortunately, I cannot find that product key anymore. I need to re-install windows 10. Will it be automatically activated after the installation, if I skip the step of asking the product key during the installation?

In my opinion, I believe that my laptop will have a digital entitlement stored on the Microsoft Activation Servers and this will not be a problem. Is that true?

If not, please suggest me a solution or a workaround.

 

Windows 10 product keys and activation - and the KMS angle

Changing the product key to the generic Windows 10 product key will reset activation to the standard retail channel for activation. It might just activate (if there was a previous digital license for Windows 10 for that computer established with Microsoft). Once Windows 10 is back on the retail activation channel, then more than likely changing the product key to the Windows 8 product key using the same method may work.

 

Product key

Hi Megan,

A product key is used when activating a software.
To help us determine the appropriate troubleshooting steps that can resolve your concern, we'd like to ask the following questions:

• What product are you trying to activate?
• Are you looking for the product key to activate your Office application?
• Which version of Office are you trying to activate? To check this, you can perform the steps posted on this
  link.
• Are you looking for the product key to activate your Windows?

We look forward to your response.