1996 Land rover Discovery Alarm Issues

[Jrs4life1]

My 1996 Land Rover Discovery has an issue with the alarm. I was driving and the alarm light came on and the alarm went off. I pulled over and cut the car off and now it wont start

 

[Jrs4life1]

I tried putting the key in the door and locking and unlocking it, but only that door opened. What do I need to do