This is the existential question behind your search. Windows 8.1 reached . That means:
Many laptops that came with Windows 8 or 8.1 have the product key embedded in the motherboard's BIOS/UEFI. Use a tool like ProduKey from NirSoft removewat+226+windows+81+install
In some cases, genuine errors are caused by specific Windows updates (like KB971033 on older versions), which can be uninstalled through the Control Panel to stop "non-genuine" notifications. This is the existential question behind your search
: A system restart to complete the modification of core activation files. Risks and Security Warnings removewat+226+windows+81+install