Please see my comment to the question: apparently, the question is not correctly formulated. But most likely, you are looking for this:
http://msdn.microsoft.com/en-us/library/system.windows.forms.form.activate%28v=vs.110%29.aspx[
^].
Want an advice? Avoid using more then one form in your application. Make one form and change it content by having different panels with different controls; you would need to show and hide panels depending on the state. Another good option is to use, instead of multiple forms, different tab pages using
System.Windows.Forms.TabControl
.
—SA