Updating MOSS license from Trial to Standard/Enterprise fails!

So finally the 180 days trial ends and you would like to update or rather convert you MOSS license from Trial to standard or enterprise edition. Well that’s pretty straight forward one would say just :-

1. Navigate to SharePoint Central Administration.
2. Go to the Operations tab
3. Under Upgrade and Migration click Convert license type
4. In the Enter the Product Key enter the 25 character license key and click OK.

Pretty straight forward but i have seen sometimes it fails and  gives you a very generic error message Your license conversion operation failed. Check the error logs for details. So after checking the Event Log you see the following

So now you are wondering what do i do, a Google search gives you some answers like a simple IIS Restart solves the problem, for some it might not. Even restarting the “Windows SharePoint Services Timer” service does not solves the problem.

For Few restarting the entire server somehow solves the problem.