make security on c# project

I made commercial windows application project in c#( visual studio 2010), and i want to make online security on it. I want to sell this product in CD's (I made setup to it and i can copy it on cd's to sell it) when customer buy this product it must work just for one user (each cd must be just for one user ) this maybe use the mac address for the computer when he(she) download the project in his(her) computer, then it must check online this product if it used for the first time or not, if it used for the first time then the user can use this project else he cannot, alredy i can made php website with all keys that can check online if the user download this product on another computer or not.(it work like kaspersky registeration but without update). summery: I want just the code in c# to secure my project online).