Activating Windows 10 Pro - Replacing Old Key Value

1. click windows button , then type cmd , and then open command prompt as administrator

   (right click command prompt). 

2. type this following steps (only type the bold texts) :

   slmgr.vbs /upk   

(this command will delete your old activation key), and then

   slmgr.vbs /ipk (your new working activation key)

slmgr.vbs /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

after these steps, check windows setting activation again