First try changing the product key.
Product Key Number - Change
If that doesnt help, try recreating the Licensing Store:
1) Click on Start orb and type cmd.
2) Right-Click on CMD.exe in the results and select Run as Administrator.
4) Type: net stop sppsvc
and hit Enter. Select Yes if prompted.
4) Type: cd %windir%\ServiceProfiles\NetworkService\AppData\Roaming\Microsoft\SoftwareProtectionPlatform
and hit Enter.
5) Type: rename tokens.dat tokens.bar
and hit Enter.
6) Type: cd %windir%\system32
and hit Enter.
7) Type: net start sppsvc
and hit Enter.
8) Type: slui.exe
and hit Enter.
9) The Windows Activation dialog will now appear. You may be asked to reactivate and/or re-enter your product key or activation may occur automatically.