How do you intend to distribute it?
If you wish to protect the individual programs, you could set up a website and make anyone who uses the product activate it on the internet like WinXP but you would need to include a individual number in each product, meaning recompiling the project so you can change the GUID or even better, add a attribute of your own, the product will present an activation wizard when it runs for the first time and ask you to activate it then it connects to the server, submits the number which the website stores in a database of active codes then the program can create a file, some where important such as System32, to store HasBeenActivated = True but use Cryptography(Remember to store the code of the program in the dll to prevent the file being copied to another computer and used on a program with a different code) and call the file MyProgram.dll as to throw off suspicion. If you can also submit the Serial for Windows or something similar like the serial for the BIOS chip or some rarely changed piece of hardware such as the harddrive(or preferably 2 or more so that the product can still be reactivated even if the windows version is changed) so that the program can reactivated over and over again but only on the system with the matching number components
BTW. Sorry about the length but the theory is quite complicated