I would suggest that as the alarm has not been used for a minimum of 2.5yrs that it is very unlikely to be in working order.
Not least it would not seem to be powered (no lights), therefore the battery inside the box is going to be dead along with the battery inside the outside box.
The only sensible way to go would be to find a local company who would be prepared to have a look and give advise/get it working.
I expect you could find the manual via Google but I'm sure you would not find all the information you would need to get it going.
Good luck
acorn
April 2009