Install win 8 in a bios without csm launch

My problem is that I want to install a higher version of win 8, respectivily win 8 pro in a computer that already came with another version of win preinstalled (win 8.1). It's possible to do this in a bios that prevents csm launch.

Welcome to EightForums.

No need to reset the UEFI/BIOS to upgrade to Pro

To upgrade Windows 8 core, you need to use the Pro Pack.

To upgrade to Pro Pack
No install files needed.
Only the Upgrade key is need.

http://www.eightforums.com/tutorials/6673-add-features-windows-8-a.html
or
use the Windows 8 Pro full version key.