INT 2F - AD-DOS - GET AND RESET VxD API STATUS
        AX = 0C20h
        CF set
Return: AX = status
            0000h successful
                BX = VxD API Status
                    0000h no error
                    0001h error
                    0100h neither Windows 3.X enhanced mode nor
                                Windows/386 2.x is running
                    0200h VM API entry point found
            0020h otherwise
Note:   this call resets the VxD API Status to zero
SeeAlso: AX=1607h