95 Escort LX Alarm wont deactivate

I just bought a 1995 Escort LX. After 2 days, I seem to have activated the alarm, which now sounds whenever i open a door or fire the ignition. According to the manual, just unlocking the door with the key should de-activate it, but it doesn't!

Does anyone have any ideas as to how I can fix this? My neighbours will be eternally grateful!

Why don't you activate the alarm, trace the sound to the audible device and cut the wires.