You could do something simple like create a hidden form that launches when the application opens, and then checks the date. The first time it opens, it stores the date somewhere. If the date is greater than the initial date plus 30 days, then do Application.Quit, otherwise, open the main form and close the hidden form.
I would store the initial date in a label on the hidden form.
Then you need to turn the .mdb into a .mde to prevent anyone from messing with the code.
The issue is how the data entered by the customer during the trail period is retrieved. You might create a routine that retireves the data from the mde file, and check this first to see if that works.
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