If the demo doesn't work, the unlocked version won't either. That's why I always recommend installing the trial before buying the game.

What kind of problem are you having with the demo? There are some things that you could check to see if you could get the game to run. This post has everything that we currently know to check to resolve problems with Fish Tycoon for Windows. If you still have problems after making sure that your system is configured properly, or if you're having a different kind of problem, please post back here or contact me via Private Message on the forums.