Hi dufino,
I am not from Laminar Research; just a flight simmer from downunder.
Are you logged in as the Administrator? Have you disabled all of your antivirus and malware software? If no to either or both questions you need to do so.
Remember that when you have installed the Disc version, disc (DVD) 1 has to be installed in the drive at all times for X-Plane to run.
Glenn