First of all, thanks for all the replies.
Hell yeah. We are trying to make this on XP, but we tried it in dos too, but its the same.
The main problem is that on my friends videocard ( nvidia geforce 6800 ) we cannot put even a pixel out in higher VESA resolutions than 640*480.
The simplest code we tried was this and it did not work of course ( on his pc ):
[pascal]
asm
mov ax,4f02h
mov bx,11bh
int 10h
mov ax,0a000h
mov es,ax
mov cx,32768
xor di,di
mov ax,0ffffh
rep stosw
end;
[/pascal]
But it still does not work. He has a blind screen.
--------
But my other problem is that the way cronodragon mentioned is a bit slow. Gonna post the unit in the next post.