Have not tried C-script much with A7, but with Lite-C I don't have problems running full screen or setting video modes.

Code:
#include <acknex.h>
#include <default.c>

STRING* MyAppTitle = "Yet Another Lite-C Application";

function main()
{
	video_mode = 7; // 800x600
	video_screen = 0;
	video_window(vector(375,350,0),NULL,112,MyAppTitle);
	screen_color.blue = 125;
	
	level_load("world.wmb");
	wait(2);
}


Maybe you have set the command -wnd in WED/SED/VC?

smile