Running an external program inside another form

The easiest way to do that would be to convert the form to a user control and add the user control to the tab in which you want the form to appear; else that or rebuild your application as an MDI application where you can open both forms up within the MDI parent's workspace. 

The user control conversion should work if the form does not contain anything that will foul up a user control (like a menustrip control).  You cannot add a top level control (a form) to control so you will have to go the route of the user control or switch to an MDI application.

To convert the form to a user control, open the code view on the Form and change one line; where the form is going to show that it inherits from Form, change it to inherit from User Control:

public partial class Form2 : UserControl