You can try this:
Honda Civic alarm reset.
Firstly, you'll have to turn the Civic's alarm off for a few seconds.
Then you'll have to poke around under the dashboard to find a small button or toggle switch.
It should only be a small switch and is most likely red or black in color.
When you have found the switch, turn on your car's ignition.
Once the car is running, you should press and hold the spring loaded button in.
Keep holding the button in, until the alarm beeps just once.
This will disable the alarm entirely. A LED on the dashboard should confirm the alarm has been disabled.
Repeat these steps to reset and hence re-enable the alarm system.
Once this is done the alarm should have reset, and hopefully would have rectified any problems you have had with the alarm.
This is one of many suggestions available on the webz.
bob