Only allow application to run on a specific system

Hey I’m trying to create a useful license system for a program I wrote In C. My first idea was to do this with some sort of a key file, that will lock the program to a specific system so it won’t be able to run on other systems without the right key file.

I was thinking about including stuff like MAC addresses, HDD serial and maybe some other stuff into the key file. Because that won’t be easy to spoof, I think ?

I have been trying a lot of things but so far none of them have been useful because it’s too easy just debugging my program and find out how the key file is validated. And from that point it’s no problem to create a program that’s able to generate valid key files.

Do any of you know or have some ideas how to create a program that’s only able to run on specific system ?

sorry for my bad English… :|