How to Active Windows 8 Pro (Upgrade) on a Clean Install

If you use the Windows 8 Pro Upgrade to install on a clean PC (or VM), and can't activate it because you get the following error:

Code: 0xC004F061 

Description: The Software Licensing Service determined that this specified product key can only be used for upgrading, not for clean installations.

...then here are the steps to workaround the issue:

1. In Windows 8, press [Windows Key]+[8], and type REGEDIT. 
2. Navigate to the registry key HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE 
3. Change the value of MediaBootInstall to 0 (it's default value is 1) 
4. Go to the Start screen and start typing "Command Prompt" (this will cause the search for apps sidebar to open up and on the left the [Command Prompt] application will appear. 
5. Right click on [Command Prompt] and choose "Run as Administrator" from the bottom 
6. Type: slmgr /rearm and press [Enter] 
7. Click OK when the window comes up to tell you that windows has been rearmed. 
8. Type: shutdown -r and press [Enter] 
9. Once Windows 8 has restarted, login and run activation again. 

Your Windows 8 Pro will now be activated. Enjoy!