A combination of three API functions:
ChangeDisplaySettings
EnumDisplayDevices
EnumDisplaySettings
can do that.

* The ChangeDisplaySettings function changes the settings of the default display d...
DECLARE INTEGER ChangeDisplaySettings IN user32;
STRING @ lpDevMode,;
INTEGER dwflags

* The EnumDisplayDevices function lets you obtain information about the display de...
DECLARE INTEGER EnumDisplayDevices IN user32;
STRING lpDevice,;
INTEGER iDevNum,;
STRING @ lpDisplayDevice,;
INTEGER dwFlags

* The EnumDisplaySettings function retrieves information about one of the graphics...
DECLARE INTEGER EnumDisplaySettings IN user32;
STRING lpszDeviceName,;
INTEGER iModeNum,;
STRING @ lpDevMode

FoxPro example:
How to change display settings: screen resolution, screen refresh rate
http://www.news2news.com/vfp/?function=-1&example=374