01. Type cmd in Start menu.
02. Right-click on the first result (cmd.exe) and click on Run as administrator (confirm by clicking Yes if required).
03. Type the following commands in cmd and hit enter after each intruction:
slmgr -rilcnet stop sppsvccd %windir%\ServiceProfiles\NetworkService\AppData\Roaming\Microsoft\SoftwareProtectionPlatformrename tokens.dat tokens.baknet start sppsvc
04. Restart your computer 2 times.