kasracer,
I understand that all, but I just need to prevent users from simply giving the application to his friends, etc.

The people range for this program isn't big, tipically they would be middle-aged women

So, for now, the main problem is to get only the local adress, because, I don't think it is being changed much ofthen But for laptops - wireless is being disabled/enabled pretty often.. its just a click of a button...