The alarm system won't shut off, and the car won't start.
If the alarm system will not turn off, and the car will not start, I would first try unlocking the driver side door manually with the key, and if it has a remote, checking to see that the remote's battery has not died. If both of these things seem to be okay, I would recommend having a professional technician, such as one from YourMechanic, look over the vehicle, as this problem could be electrical in nature.
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