Car Alarms: Need help with a 1995 Infiniti J30 alarm., 1995 infiniti j30, infiniti j30

Question
Okay, so I just bought a 1995 Infiniti J30 model. It's a great car for me and everything but one thing. I've had it for about 3 weeks now and have put it through the shop to make sure nothing was wrong with it, ending up to have a little bit of work on it. So now that I've been through that and stuff yesterday I went to the store and when I came back out I went to go open my door which was unlocked and the factory alarm started going off. Now the place I got this car from didn't tell me that it had an alarm or anything of the sort and I don't know how to disable it or anything like that. It's not going off anymore and I was able to start it back up sometime later and drive it back home but still. So I guess my real question is how do you pretty much unhook the factory alarm on a 1995 Infiniti J30 for good? Or is there such a way that I can go and buy a key fob and like um, pretty much program it or something to work for my alarm? That way I can keep the feature but be able to control it.

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?

Or,

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

Let me know more on this to better
advise you.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com