To provide a method, for a computer system to which a plurality of display devices can be connected, for managing the power supply to individual display devices. ÄConstitutionÜ For the configuration of the present invention, as a further determination condition, resource information is added, concerning the positions (524 and 532) of a mouse pointer and of an active window, to a determination condition of a current screen DIM/saver that constitutes the operating state for a keyboard/mouse. The positions of the resources on a plurality of screens are determined, and when they have not been displayed on a specific monitor for a specific period of time, that monitor is moved to a low power consumption mode (a low power operating state). According to one aspect of the present invention, a computer that can be connected to a plurality of display devices comprises: means for determining whether screens of the plurality of display devices satisfy a predetermined condition; and means, based on the result obtained by the determination means, for changing the operating state of at least one of the display devices that satisfy the predetermined condition.