Make a window the active window

Question

How would i make so when i click a button it makes a window the active window, i mean a window of a program that is  already running. 

Any help would be greatly appreciated

Answer 1

 Microsoft.VisualBasic.Interaction.AppActivate("App Title or ProcessID")

Answer 2

As John mentioned, you can call AppActivate from Microsoft.VisualBasic.dll,
Just be sure to add it to your References, If you try "Add Reference ..." you
will find it in ".NET" page tab in new window.

If your application is minimized, it will be activated but it doesn't come up (Restore).

http://www.floresense.com/resc_center/?art=1353