This simply requires that you increase the screen resolution of your monitor. It is probably set at something like 640x480. Simply right click on a spare section of your desktop & click properties. Go to settings and increase the screen area. It should be right at 600x800. If not, take it up another notch.
If you cannot get it up past 640x480, it means you have not got the correct video drivers installed. Windows can defaults to a generic 640x480 16 colors on setup if it cannot locate the correct drivers.