How to make a trialware? [duplicate]

Question

Possible Duplicate:
how can i make my product as a trial version for 30 days ?

Dear all,

Recently I have developed a software for windows and I want to make a trial version out of it for advertisement. The trial version I have in mind should be runnable only for 30 days for example. I myself have an idea about saving the time of the system in a file or in the registry of windows, but changing the time of the system can also make my program confused.

What do you suggest ?

Thanks in advance

Answer 1

using registry or any other recource on client system can make your software easy to crack Instead of that you may write a licence server and your application can check the licence over that server for each run..