Learning center dialog is always displayed,no matter how many times it is closed.The tutorials seem to show a 'Dont show again' option but i do not see that.Is there any other way to turn it off?

Hello,I was using the tech preview download a few days back and it worked fine.But today after installing the update I am being asked to enter a serial number.I dont find it anywhere in my subscriptions or any of my emails.can someone guide me here? ...