int xScrn = GetSystemMetrics( SM_CXSCREEN );
int yScrn = GetSystemMetrics( SM_CYSCREEN );
/*
SM_CXSCREEN,SM_CYSCREEN Width and height, in pixels, of the screen of the primary display monitor. These are the same values you obtain by calling GetDeviceCaps(hdcPrimaryMonitor, HORZRES/VERTRES).
*/