I'll just "chime" in here rather then finding my old post and just confirm that a new battery solved all my alarming problems. (well, on the Xfire, anyway). I had the situation where it would go off randomly and in spurts, dying bird chirping, that whole scenario. I couldn't get the fob to work or start the car (without a boost) and even when it was boosted and started, the alarm would pull the same stuff after turning the car off and trying again.
Simplest solution is what I should have tried first - new battery!