Car Alarms: VOLVO ALARM SYSTEM, alarmtek, dash area

Question
My husband's 2000 s80 Volvo alarm keeps on going off for no reason.  He has had it checked and, not surprisingly, they want to replace it for $400 or more.  We think it would be a better idea to just unhook the blame thing!  The question is, how do you unhook it properly?
Thanks!

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