Click the Start Menu or Press the Windows Logo on the Keyboard, then type “Command Prompt” and select “Run as Administrator”
Type the command “slmgr /upk” and wait until the notification “Uninstalled product key successfully” appears.
Type the command “slmgr.vbs /cpky” and wait until the notification “Product key from registry cleared successfully” appears.
Now you can activate Windows with peace of mind without worrying about previous cracks/licenses.