INT 17 - INSET - EXECUTE COMMAND STRING                                         
	AX = CD00h
	DS:DX -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. command string (max 80 bytes)
Return: CX = 07C2h (1986d)
Note:	user interface menus pop up after last command, unless that command
	exits INSET