Windows 10: I got a new motherboard and now my windows isnt activated, i have lost my product key

I just got a new motherboard today and installed it, when i turned on my pc it has the activate windows watermark and when i run the troubleshooter does nothing, i lost my product key as i purchased it from ebay sometime ago, is there anyway i can fix this or do i have to re buy windows?

:)

 

Lost Windows Activation Product Key

I recently lost my Windows 10 pro Activation product key and now Microsoft wants me to activate my windows but now i dnt have any product key please suggest me the way i dnt want to lost my all data...

 

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.

 

New motherboard: Windows key doesnt work

So i installed a new motherboard yesterday, and now my key isnt activated. It was activated before i installed this new motherboard