Windows 10: how to activate a windows 10 upgrade on a previous copy of Windows 7 E

I have a PC that had a copy of windows 7 Enterprise on it. I did the upgrade to windows 10, but am told it is not activated and it won't activate.
I need to know if I can buy an OEM version of windows 7 or 8 and activate using it's key, or if I can buy the full version of windows 10 which is for new installation, and use it to activate? I do NOT want to reinstall new since I have many programs I do not want to reinstall.

What is the best way to go abut activation?

:)

 

active widows 10

You need to re-install the previous OS, then upgrade to win 10.

This product key didn't work. (Error code: 0xC004C003)

License could not be found or was invalid. (Error code: 0xC004F034)

What it means and how to fix it

There are a few reasons why you might see this error:

• 
  You performed a clean installation of Windows 10 instead of first upgrading from your previous version of Windows. When this happens, we aren't able to register your entitlement with the activation servers because you aren't upgrading to Windows 10. To fix
  this, you'll need to go back to your previous version of Windows, make sure the previous version is activated, and then upgrade to Windows 10. For more info about how to go back to a previous version of Windows, see the section in
  
  Recovery options in Windows 10.
  
• 
  You upgraded to Windows 10, but the activation servers were busy. If you upgraded from an activated copy of Windows 7 or Windows 8.1, your copy of Windows 10 will be automatically activated, or you can wait a while and then select Activate now. If you performed
  a clean installation instead of first upgrading to Windows 10, see the info on how to fix this problem in the previous item.
  
• 
  You might also see this error if you're using an invalid product key. For example, you can't use a Windows 7 or Windows 8.1 product key to activate Windows 10.
  

 

Windows Upgrade Activation Failed (Error code: 0xC004C003)

How did you upgrade to win 10? Did you use the windows update or the ISO?

This product key didn't work. (Error code: 0xC004C003)

License could not be found or was invalid. (Error code: 0xC004F034)

What it means and how to fix it

There are a few reasons why you might see this error:

• 
  You performed a clean installation of Windows 10 instead of first upgrading from your previous version of Windows. When this happens, we aren't able to register your entitlement with the activation servers because you aren't upgrading to Windows 10. To fix
  this, you'll need to go back to your previous version of Windows, make sure the previous version is activated, and then upgrade to Windows 10. For more info about how to go back to a previous version of Windows, see the section in
  
  Recovery options in Windows 10.
  
• 
  You upgraded to Windows 10, but the activation servers were busy. If you upgraded from an activated copy of Windows 7 or Windows 8.1, your copy of Windows 10 will be automatically activated, or you can wait a while and then select Activate now. If you performed
  a clean installation instead of first upgrading to Windows 10, see the info on how to fix this problem in the previous item.
  
• 
  You might also see this error if you're using an invalid product key. For example, you can't use a Windows 7 or Windows 8.1 product key to activate Windows 10.
  

 

If you have 1511 you can just use a key to activate 10.

 

You would have to buy a years MSDN subscription (for $1200) or a minimum of 5 licenses to get enterprise.

You can't upgrade from enterprise to pro / home and you can't use such a key to activate enterprise. You would have to clean install if you bought a retail key.