I need an idea to make my trial software. It's not only a trial because I need ir for my tesis. The problem is this:

Last year the teacher who was in charge to correct these apps sold and application to a super market therefore I don't want this to happen to mine. Could someone please suggest me a security mean.

I was thinkin about a way of extracting the name the user gave to windows during the setup and making the app unable to work with other names... what can you tell me about that?