The demo disc is the complete system but you will need a dongle and purchase SeaPro for full working system. The demo gives you an overview of how it works. I have been using SeaPro for many years through all its changes and it is a wonderful piece of software. If I can help in any way then email me direct at steve@albinvega.com
I fiddled with the demo version for a while and then decided to buy the real thing.
So far I'm impressed with what I see except for the tidal info. I didn't buy the tidal mudule and was told that if I entered the tidal harmonic constants manually it would do local predictions. If it does, I'm too dumb to find out how.
The one thing about the demo - it will not see NMEA from your GPS. Only the real one does.