How to recognize window on the screen

    I'm trying to finish a program which can do actions on the computer screen as your wish. So the program need to have follow abilities:
    1. Recognize the graphs on the screen. Get the position of special component, such as windows, title bar, menu, button and so on. Especially, the program need to recognize words written in the graphs.
    2. Do actions as you programed, such as open a window, select a menu and so on.

    So, the first step I need to do is to get my program recognizing the windows frame.
    At the begging, I thought the windows frame is surrounded by the black line. So I compare the Pixels arounding to get a frame by the same colour. But then, I failed, because the windows frame is not surrounded by a black line. So  I get the idea that we can see the windows frame by our eyes is because the color inside the window frame is different from the color outside the window frame. I turn my idea to codes, and I can recognize the window frame then.