Alarm wont shut off and I can't start vehicle

You need to take it to the dealer or have a mobile lock smith program the new key's . Transponder chip in the head of the new key . If the computers - PCM / ECU an the BCM do not get proper code it won't let the vehicle start .

retry replacing battery new doesnt mean cant be defective if it is good than fob needs a relearn different cars have different relearn that you can perform but if the fob has other features such as start that will have to be done at dealer ----
Free Keyless Remote Fob Entry programming instructions procedures for all... look up your vehicle and will have instructions one how to program fob --will also tell if need to be done at dealer

use ur key to open the driver side of the door while door is open,,,it should shut off

With alarm activated your ignition is disabled.Find the combination to disable it.With GM's you hold opposing buttons on the fob till it beeps twice. The dealer should help for no charge.

You can try to use another key if you have one, get one made. Also try to lock and unlock the doors, if this does not help you will need to bring vehicle to shop with high end scan tool so they can monitor what part of the security system is activating. Thanks

Is this a factory installed alarm system? If so, unlocking the driver door with the key will allow the car to start. If not then you will have to remove the aftermarket alarm system to start the car.
If you have a factory alarm system you can get a new FOB (key chain alarm button) from a ford dealer, but it must be programmed using a scanner , before it will work in your vehicle.

Alarm Module Reset Procedure
NOTE: This information applies to a Vehicle Theft Security System (VTSS) that was armed when the battery was disconnected and reconnected.
When the armed VTSS senses that the battery has been disconnected and reconnected, it enters its power-up mode. In the power-up mode the alarm system remains armed following a battery failure or disconnect. If the VTSS was armed prior to a battery disconnect or failure, the system will have to be actively or passively disarmed following a battery reconnection.
The power-up mode will also apply if the battery goes dead while the system is armed and battery jump-starting is attempted. The engine no-run feature will prevent the engine from starting until the alarm system has been actively or passively disarmed.
Passive disarming of the Vehicle Theft Security System (VTSS) occurs when the vehicle is unlocked using the key to unlock either front door or the lift gate. Active disarming of the VTSS occurs when the vehicle is unlocked by depressing the Unlock button of the Remote Keyless Entry (RKE) transmitter.
Once the alarm has been activated (horn sounding, lights flashing, and the engine no-run feature), either disarming method will deactivate the alarm.
Depressing the Panic button (if equipped) on the RKE transmitter will also disarm the VTSS, but the horn will sound and the lights will flash for about three minutes as part of the Panic feature. The horn and lights can be stopped by pressing any of the RKE transmitter's buttons or driving the vehicle above 15 mph.

replace the battery in the key fob and unlock the car with that, if u last locked the car with the key fob, you armed the alarm and can only be disabled by unlocking with the key fob, the car wont start because its an anti theft feature.

If you use the drivers outside door lock to unlock the vehicle it should disarm the vehicle. emmissionwiz is correct, you can't simply shut the factory alarm off.

you need the remote control of the alarm to turn the alarm off.

you may need to change the battery of the remote in case it would no longer control the alarm or if you have a valet switch to turn off the alarm, then use it.

the immobilizer is working that is why you can not start the car.

tnx 4 using fixya,

drcool