>Hello, i need to give the demo of a program i made but i want that after 2 months doesn't work or allow to work, how can i do this?

Hi Edgar,

The first idea which comes to mind (no implementation details, idea only):

On the fisrt run of your application store the current date in the registry.
Each next run read this date and compare with today's date.

Disadvantage of this idea:
1) The application would work fine on another PC
2) Users can quite easily hack it.

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You can use the similar idea but with ini file instead of registry or with some file.