INT 2F - WinDOS v2.11 - TURN VIDMEM OFF                                         
	AX = AF04h
Return: AX = status
	    0000h successful
	    0001h video memory is in use
SeeAlso: AX=AF00h"WinDOS",AX=AF03h"WinDOS",AX=AF05h"WinDOS"