Set a window into the foreground and activate the window.
For some windows this action may result in the icon in the taskbar flashing to indicate use attention is required rather than putting the window at the top of the Z-order. To put a top level window into the foreground, use ShowWindow.
notepadWindow = FindTopWindow("Untitled - Notepad"); // find the top level window
notepadWindow.SetForegroundWindow(); // this will ensure the window is in the foreground and activated