Car Alarms: After-Market Car Alarm, valet mode, nissan altima

Question
I own a 1998 Nissan Altima with an After-Market car alarm. My keys were stolen and I would like to disarm the car alarm so that the key less entry will not work so no one can steal my car. Also, I need to disarm it because my spare key (which is a copy) sets the alarm off every time I unlock the car.

There are no fuses in the fuse box for an anti-theft system.

How would I go about disarming the system so that the key less entry won't work and I can use my spare key without setting off the alarm.

Thank you so much!

-grateful college student

Answer
Right, Ok, try this.
Put the key in the ignition, and turn forward
all the way just before cranking. Then within
5 seconds, press and hold in the valet/override
button, found under the dash area, usually to the left
of the leg, drilled into a plastic panel.
Might even be part of an on glass antenna
in the windshield if it's a remote starter,
until the installed LED (the blinking light)
in your dash area goes off, and the siren chirps twice.
(Your valet switch might be the toggle (on/off) type.
in this case, key on, flip switch in opposite direction,
key off.)

This should reset the alarm and allow you to
go on your way.

Just Repeat these steps to place it
back to valet mode.

That should do it.

Good luck.

ALARMTEK