Abstract: The present invention provides a method of turning over a window that is laid over another window in order to peek a content of another window that is laid under the window in a pseudo-three dimensional manner, in a multi-windows computer system. The method includes the steps of (a) selecting a first window from the multi-windows by placing an object on the first window; (b) clicking the object on the first window to initiate an operation of turning over; and (c) dragging the object toward a direction to which the first window is to be turned over so as to unveil a second window that is laid under the first window, whereby enabling to peek a content of the second window.