Air conditioning system can't control

When I drive my car, Nissan Stagea 300rx, it suddenly operates its air conditioning system, even if I have never touched the button concerned, to be honest. In the meantime, its audio system also shuts down. At the first time this problem happened, I tried to detach its minus cable from the battery. Fortunately, this problem was gone. But a few day later, it happens again. Thus, could you let me know what is the best solution for that?