To prevent a user from sensing change in feeling of operation of a pointing device. There is provided a computer system control method for controlling a computer system having a coordinate designation system for producing base data for calculating position coordinates, the method comprising the steps of obtaining the position coordinates calculated based on the base data; when a predetermined application program is activated from another application program, obtaining position coordinates notified by the other application program, and showing a designated position image on a display screen based on the position coordinates obtained; and when the predetermined application program is activated from an operating system, showing the designated position image on the display screen based on the position coordinates obtained at the step of obtaining the position coordinates.