Car Alarms: Auto Alarm/98/Buick/Century, alarmtek, buick century

Question
Looking for default and user information.For no apparet reason, the alarm goes off when you use the key to open the door, goes thru the cycle and then goes off about every 15 seconds. I disconnected the battery hoping it might set a default mode. Additionally, when the alarm goes off you cannot start the car.   HELP!

Answer
Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Is it: Headlights flashing, car horn honking
and a worded SECURITY" light in the dash flashing?
(doubtfull since none of the notes show this
car as having a factory alarm system)=FACTORY

Or,

is it: flashing parking lights,
an LED in the dash area, and a siren
going off?= AFTER MARKET

Let me know more on this to better
advise you on a course of action
to take.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com