Glad you got it working again. definitely replace the battery and if your not 100% confident that everything is ok, get it serviced by a professional.

earlier ade panels had a tendancy to freeze and lock out, it was probably down to pot luck if yours did'nt, what you describe is a classic case of this problem, all you need to do is shut down your system from the mains,disconnect your battery then power up the alarm again with both your mains and battery reconnected as a precaution it is always best to replace your battery but i think you would probably be better to re-invest in a new battery to fit into another new upto date alarm panel instead!!. hope this is helps.