Windows 10: Win 8.1 product key not accepted after installing Win 10.

I did run update from Windows 8.1 to Windows 10 on my HP desktop computer. Now the system says I have to activate the Windows with the product key and when I insert the old product key it gives error message. Windows was preinstalled to the computer. There is no visible way to sort this out. The update was advertised as free.

:)

 

Fresh Install of Win 10 without Serial Key?

Looking to reformat a laptops HDD, and then reinstall Win 10 fresh. The problem is it came pre-installed with Win 8 and I did the free upgrade to Win 10. How exactly would I re-format the HDD, reinstall Win 10 and ensure it reactivates properly? I don't see a Win 8 serial key anywhere in the contents of the box.

 

Win 10 is not accepting win 7 starter product key

I just installed a clean installation of win 10 from a USB drive on my old netbook, win 10 works really good but the win 7 starter product key on the back of netbook is not being accepted by win 10. What should I do ?

 

Win 10 Pro upgrade using Win 8 Pro product key

I just bought a new computer running Win 10 Home. When I went to upgrade to Win 10 Pro using my Win 8 Pro product key from my old computer, the upgrade wouldn't activate.

Now I'm stuck with a bunch of error messages (mainly 0xC004C003) and am being told windows isn't activated. I can't seem to get my activated Win 10 Home back.

I don't have a product key for the Win 10 Home because it came pre-installed. There's no product code recorded on the packaging or labelling on the device.

So:

How do I either

• activate the Win Pro upgrade, or
• Get my activated Win 10 home back?