INT 2F - Windows95 - CHECK MS-DOS VERSION 7                                     
	AX = 4A33h
Return: AX = 0000h for MS-DOS 7.00+
	    (officially) BX,DX,SI,DS may be destroyed
	    (undoc) 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. primary shell executable name
	    (undoc) DS:SI -> CONFIG.SYS SHELL= command line (counted string)
	    (undoc) BH = ??? (0000h)
	    (undoc) BL = ??? (0000h)
	AX nonzero (usually 4A33h) if MS-DOS 6- or other DOS
SeeAlso: AX=1611h,INT 21/AH=30h