Car Alarms: reprogramming factory alarm if possible, bright headlights, nissan maxima

Question
I have a 93' nissan maxima (4 door) which I bought from a private owner.  Well, I was leaving work and I put the key into the door to unlock the doors, and the factory alarm (I'm assuming that is what it was)started to sound and the bright headlights were blinking on and off.  I don't have a keychain button to turn it off (if there is one)I noticed the two front passenger doors have a keypad but i dont know the code. I tried to start the car, but to no avail.  So I closed the door and eventually it stopped.  I tried to open the car with the key again and the same thing happened.  I was wondering if i could reprogram the keypad, if thats what deactivates the alarm because the previous owner is in the hospital and i cant get the code.  I also wanted to know is there a alarm keychain botton or does the keypad on the door deactivate it?  Also, if I cant reprogram the keypad or what ever controls the alarm, can I disconnect it?  what can I do to avoid it going off?  For now, I removed the fuse for the alarm which also took away the power to my radio and the digital clock on the dashboard.

Answer
Dear August.
  ok then, set off the alarm on purpose. Then
in the drivers door, turn the key all the way left
first, then to the right. This should turn off the
factory alarm system. To permanantly disable
the factory sytem, go to your local car alarm
guys, and have them ground the
FACTORY ALARM DISARM WIRE|lt.grn/blk/ w. sil dots|- |
@ the anti-theft module located to the left
of the steering column under the dash.

This will stop all the brew ha ha going on with this system,
but then leaves you vulnerable to car
theft if left like that.

I strongly suggest once done,
you put in an aftermarket system you know, understand,
and that will add convenience and security to this car.

Good luck with it and let me know
if this solved it for you.

ALARMTEK
CARALARMCITY.com