I received a "Windows must be reinstalled to activate" message.


If Windows is not automatically activated, you can resolve the issue without rebooting.

An the command prompt do the following:

Type: net stop slsvc  (It may ask you if you are sure, select yes)

Type: cd


Type: rename tokens.dat

Type: cd %windir%\system32

Type: net start slsvc

Type: cscript slmgr.vbs -rilc (It may take a long time for this to complete, please be patient)

The license should now be able to be reactivated without full reinstallation.