how to Implement trial days for app for 30 day then stop it

I make desktop application using csharp .

I face issue I can't protect this desktop application I do it from another client use it.

so I ask about way that I can do to prevent another person use it

so what I do to protect my app

so how to give client 30 day as trial then after that if not pay stop it
can you tell me how to do that

What I have tried:

some developer store data on registry

are this best solution for that store on registry or what

if user change date time of windows how to handle that

can I prevent user from install my app again

can any one help me by answer this question by more details

if free or source code or library can use it without pay then I prefer that