I don't think you need to paid the money to buy the third party license control like ActiveLock.

Because, you can always write all the information into a encryted text file and store it inside the windows system directory. Which is seldom user will access this folder to look for the licensing file. If you like to store this into window registry it also not a problem, provided you've encryted it.

I personally, feel that the following information is important for a software eveluation/licese control.[*]Date/Time for the application installed.[*]Number to user support (For those application that support multi user.[*]Evaluation days (For those beta version.)

Upon you've logged all this information, your application should check it everytime it start.
Once found that the system date different is greater than the number of given eveluation date, then your application should write a extra data (Like "Expired" word) into this license file to indicated that the eveluation period is over and stop proceed loading your application.

With this method, if the user change the system date, it also won't be able to run your application. Or event they reinstall it. But this method still can be hacked by reformat the PC. This because there was nothing is call Secure in this world.

So, should you think abt this method? I did this in my distributed application. I even create my own license number (Product ID) which included all the information as I need to verified the distributed application.

Cheers.