Britec Tech Support Forum

Him is it possible to install a fresh copy of windows 8.1 using a windows 8.0 code or is the only way to install 8.0 then do all the updated then upgrade to 8.1 and do more updates? If I've already updated to 8.1, does the windows product key change? Would it be possible to backup my 8.1 with advanced tokens manager and install windows 8.1 from the all in 1 disc from Microsoft as a 30 day trial then patch that copy with my previous install again using advanced token manager?..... Just a thought to save time

You can upgrade from 8 to 8.1 
Upgrade product key only

What I ment was, can I install a fresh oem install of 8.1 with 8.0 code?

You could try this Activate retail Windows 8.1 with Windows 8 Product key.

I know with OEM machines if the computer was shipped with 8.0 and you upgrade to 8.1 you still must install Windows 8.0 first if you are re-formatting your machine.