How do i put a registration key in a vb program?

what i want to do is write and implement a registration key(license) feature like in photoshop and other expensive programs. also i want to make my program have its own file extrension to associate its files with.How do i put a registration key in a vb program?
Make the program access and add a lot of registry values in places people would never expect. If you need a non-registry implementation have the program make a folder somewhere on the computer after you enter the right registry key and refuse to work if it's not there (but don't tell the user that).