I am trying to make a form with dynamic opacity in VC#?

in the on's click event that launches the about box, after the about box has returned you want to set the form1 opacity back to 0.5 (50%). Make sure that you are launching the about box with form.ShowDialog() instead of simply using form.Show(). That way, when the user closes the about box, the next line of code will run, and that will be the line of code that resets the main forms opacity property.