An apparatus for controlling a screen of an image display device, comprising: a user interface receiving a wanted command from a user; a power unit supplying a power; a display module operated when the power is supplied through the power unit; a mode determining unit determining an input mode; and a screen controller controlling the display module such that a frame rate of the display module is set according to the input mode determined by the mode determining unit and a characteristic of the display module, wherein if the determined mode is a TV mode, the screen controller is configured to set the frame rate to a fast frame rate including 100Hz or 120 Hz, wherein if the determined mode is a PC mode, the screen controller is configured to set the frame rate to one of the fast frame rate and a normal frame rate based on a variation in motion of the screen displayed on the display module, such that when the variation in motion of the screen displayed on the display module is more than a preset reference range, the frame rate is set to the fast frame rate, and when the variation in motion of the screen displayed on the display module is less than the preset range, the corresponding frame rate is set to the normal frame rate, wherein if the determined mode is a Video mode or component mode or HDMI mode, the screen controller is configured to display an first on screen display menu for manually selecting the frame rate to one of the fast frame rate and the normal frame rate, set the frame rate to the fast frame rate if the fast frame rate is selected, and set the frame rate to the normal frame rate if the normal frame rate is selected based on a user input on the displayed first OSD menu, wherein if the frame rate is set to the normal frame rate, the screen controller displays a second OSD menu for selecting a display module, sets the frame rate to 60Hz if the selected display module is an LCD, a PDP, or a Projection, and sets the frame rate to 75Hz, if the selected display module is a CRT. a user interface receiving a wanted command from a user; a power unit supplying a power; a display module operated when the power is supplied through the power unit; a mode determining unit determining an input mode; and a screen controller controlling the display module such that a frame rate of the display module is set according to the input mode determined by the mode determining unit and a characteristic of the display module, wherein if the determined mode is a TV mode, the screen controller is configured to set the frame rate to a fast frame rate including 100Hz or 120 Hz, wherein if the determined mode is a PC mode, the screen controller is configured to set the frame rate to one of the fast frame rate and a normal frame rate based on a variation in motion of the screen displayed on the display module, such that when the variation in motion of the screen displayed on the display module is more than a preset reference range, the frame rate is set to the fast frame rate, and when the variation in motion of the screen displayed on the display module is less than the preset range, the corresponding frame rate is set to the normal frame rate, wherein if the determined mode is a Video mode or component mode or HDMI mode, the screen controller is configured to display an first on screen display menu for manually selecting the frame rate to one of the fast frame rate and the normal frame rate, set the frame rate to the fast frame rate if the fast frame rate is selected, and set the frame rate to the normal frame rate if the normal frame rate is selected based on a user input on the displayed first OSD menu, wherein if the frame rate is set to the normal frame rate, the screen controller displays a second OSD menu for selecting a display module, sets the frame rate to 60Hz if the selected display module is an LCD, a PDP, or a Projection, and sets the frame rate to 75Hz, if the selected display module is a CRT.