Windows 10 Won't Activate

[raphealq]

I had a genuine, activated copy of Windows 8.1 on my PC. I got the upgrade reserve prompt for Windows 10 but did not want to wait for the upgrade notification. Instead, I used the media creation tool here: http://www.microsoft.com/en-us/software-download/windows10. The "Upgrade this PC" option for some reason did not work as it just restarted my PC upon completion. For this reason, I used the "Create Installation Media for another PC" option

When I booted from the USB and installed Windows 10, it asked for a product key. I entered the one for my copy of Windows 8 and it didn't work. Now, my copy Windows 10 is not activated. What can I do to activate it?

Thanks.

 

[USAFRet]

When I booted from the USB and installed Windows 10, it asked for a product key.

Yes, that is what would happen.

The Win 10 Upgrade needs to be done from inside a currently activated WIn 7 or 8.1. Booting from the Win 10 USB or DVD and installing will ask for a valid Win 10 license key. Which you don't have.

How to fix? Restart the whole process.
Install 8.1, do all its updates and activation, then do the Upgrade to Win 10 again.

 

[PsyKhiqZero]

If your files weren't overwritten yet. Boot up your previous install .Try to enable "view hidden files or folder" and look in the c:\drive. there should be a hidden for labled somethig with something related to windows. If you see one with "bt" then those are the files for the reserve upgrade. Navigate the other similarly named folder for the setup.exe and start that. It's a bit of a longshot but the same thing happened to me.