Electronic Alarms and Home Security Devices - Need help with DSC alarm power source!

We had a heavy thunderstorm an hour ago and our phone line was hit. Our alarm pads are now beeping with the trouble alert, but there is no read out on the LCD screen. The *2 code lights that screen, but no trouble codes appear. Our monitoring service says we need to "unplug" the electrical plug, and take out the back up battery. We know where the battery is, but can't find where the system would be plugged into the power source. The installers who put it in 12 years ago are out of business. Any ideas?? Help - I'm going bonkers listening to the beep, beep, beep, beep..... :eek:

For now, simply take one of the wires off of the first two terminals on the motherboard (it's safe; 16vac). Then you can take your time looking for the transformer. It could in an outlet behind a piece of furniture you never move, in the garage, basement, sometimes even just above the attic access.