Should you encounter problems with activating Windows 8 or Server 2012 then have a look at the new added command-line tool licensingdiag.exe.
To run licensingdiag.exe open a command prompt and enter the following command:
licensingdiag.exe -report c:\data\licensing\licenserep.xml -log c:\data\licensing\license.cab
This will create a log file and a CAB file. The log file is an XML type file that contains various information about the client, the OS and its licensing status. The CAB file contains a copy of the log file, a file called tokenstore.dat (I was unable to find any information about its purpose) and a Diagevents.evtx that contains a dump of License related events and can be opened using Eventviewer.