Hi Clair I'd prefer to give you a guide on how to replace the battery and achieve a fully usable alarm.
This is how to mend it not kill it :)
Elderly,working system with personal attack button to hand (PA).
Think about it!!.
If on the other hand the system can't be used for not knowing the code then I'd be happy to assist you with decommissioning.
e manno
February 2014