Cant activate Win 10 despite having legit Win 8.1

[Aiden2k13]

Hi, despite of having legit Win 8.1 , I am unable to activate Win 10. I reserved my copy of Win 10 few weeks back and today I got the ISO and installed via USB drive and I selected "Clean Install" . Now when I am trying to activate win 10, I am getting this error -
Error code: 0xC004C003
I am unable to activate it when I am trying manually. It says wrong product key.

Do any of you know why I am getting that error and how did you activated your copy of win 10 ?

 

[Suztera]

You have to upgrade via window update to activate your window 8.1 key on window 10. Using the ISO will not give you an actiavted window 10 licence with a window 8.1 key.

 

[kyllien]

You will need to reinstall Windows 8 then upgrade to Windows 10. Once Windows 10 is activated you can "Reset this PC" to perform a clean install.

You can use the ISO, just make sure you start it within Windows 8 and perform an upgrade.

 

[Aiden2k13]

You have to upgrade via window update to activate your window 8.1 key on window 10. Using the ISO will not give you an actiavted window 10 licence with a window 8.1 key.

If I install win 8.1 now, can I upgrade to 10 via upgrade option?

 

[MarkW]

If you install 8.1 now, and then install all of the updates, one of those updates will check your system for compatibility with Windows 10. If it finds that your computer is compatible, it will let you make a reservation for upgrading to Windows 10. Microsoft will then invite you to download the update at a time and date of their choosing.