I bought the program but it still thinks its the demo

If you have installed the Demo and then purchased the program you must note the following:

When you launch the installer, it automatically prefills any existing serial number into the serial number field.   Thus, if you have installed the demo then the serial number it starts with is the demo serial.

When you see this screen--or the Macintosh Equivalent-- you need to change the demo serial number that is pre-filled in (shown highlighted in blue in the image below) with the full serial number that you have received with your purchase.  

ATTENTION: If you do not change it here, then the program will still think it is the demo!!!