home alarm systems?

we have an old alarm system optima xl. the problem we have is we woke up this morning alarm going off led light showing attack we entered our pin to turn the alarm off no problem but then the keypad went dead attack panel still lit.power light was still on. we turned the power off at the mains once power back on of course the alarm went off it let us enter our code to turn the alarm off .but then went dead again could not press anything any ideas