Car alarm and immobilizer

I have not used the key fobs in months because of the batteries died. However the other day I used my key to open the door and the alarm went off, now every time I open the door the alarm goes off, and car will not start due to the immobilizer. I have tried using the key in doors and ignition, I replaced the fob batteries and they did not help. everything I do will not stop the alarms, unless I unplug the negative battery terminal. Please help.