- Open regedit by pressing Windows-q, entering regedit and selecting the result from the list of hits.
- Navigate to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
- Change MediaBootInstall from 1 to 0
- Go back to the start screen and enter cmd there.
- Right-click Command Prompt and select to run it as administrator.
- Type slmgr /rearm on the command line and hit enter.
- Reboot Windows now.
- Run the activation utility afterwards, enter your product key to activate Windows.