I asked you how old the battery was,i didn't suggest you replace it,
The fault lies either with the tamper circuit or the panel can't reset without the use of the engineers code.
I also asked you if your wife had removed the PIR or removed any wiring,
If the PIR is causing this issue then it either the wiring or the rear or front/cover tamper switch is open circuit,thus causing the problem.
Defeat the tamper(two wires) and see if the panel will reset,if that tamper loop is defeated and the panel won't reset then it's set up for engineers reset.
Do you know this code?,
I asked you this in your previous post,
If you are struggling mate and don't have a meter to test the loops resistance then maybe you should think about getting someone in.
e manno, December 2012