Alarm not reseting? Optima G3 intruder sytem?

Bought a new house, intuder alarm and all electrics off at the mains. When I reset the circuit breaker on the alarm, key in the code the exterior alarm continures to sound. Purchased a new battery today as house was vacant for 8 months. When new battery attached alarm is sounding, key in the code, the panel enables but alarm continues to sound. ???