Someone might be interested... 1. Write down your current activation key (doesn't matter if you are still on Win 8.0 or 8.1 preview). 2. Grab RTM and installation key (google is your friend). Use Rufus - Create bootable USB drives the easy way to create bootable pendrive (choose UEFI compatible MBR). 3. Install it 4. Run regedit. Go to HKLM\Software\Microsoft\Windows\CurrentVersion\Setup\OOBE. Change both keys MediaBootInstall and RetailInstall to 0. 5. Run elevated cmd prompt. Type slrmgr /rearm 6. Restart as prompted 7. Launch PC Settings, go to Activation, tap Enter key button and enter key noted at the beginning. Done. Enjoy.