I have a 99 Accord with the factory installed alarm system. I have been
having some issues with it and had 2 separate incidents tonight. The
first time, I used the keyless to lock the car from the outside when I
went into the store. My teenage daughter was in the car and opened the
door from inside when I returned to the car. The alarm sounded when she
opened the door. I entered the code on the radio, but it did not
silence the alarm. I started the car, but the alarm kept going. Then
when we got home, I opened the driver's side door and the alarm went
off again. And, again, entering the code on the radio did no good. The
neighbors loved me...

Any idea why this is happening and/or how to get the alarm to stop if
the code doesn't work?