The present invention provides an excellent display apparatus effectively using the display area of the object/window in the inactive state existing on the display screen and a method for controlling the display apparatus. At least one object/window is displayed on the display screen of a display apparatus in a bitmap manner in accordance with the present invention. A determination as to whether a predetermined object/window displayed on the display screen is in an active state, or not, is always made, and the display contents of the predetermined object/window is switched in accordance with the result of the determination. For example, if the predetermined object/window is in the active state, a regular display contents of the predetermined object/window is displayed, and if the predetermined object/window is in the inactive state, another information, such as an advertisement information, is displayed. In the is inactive state, the operator does not require the regular display data of the predetermined object/window, and a display area of the display screen can be effectively used by displaying notification information, such as the advertisement information, to provide the operator with the useful information. It realizes a secondary effect in which the manufacturers of the display apparatus and the display application programs get an advertising revenue in addition to a selling profit.