Car Alarms: reset anti theft horn alarm, nissan frontier, frontier pickup

Question
I just did an engine replacement for a 2000 Nissan Frontier pickup and tried to turn over the new engine with the starter.  All instrument lights are on and everything electrical works with the exception of the starter engaging.  All that happens is the anti theft horn goes off and there is a clicking noise under the dash when I turn the key to start.  Does the anti theft device need resetting in order to engage the starter?

Answer
Sounds like an after market alarm with starter kill.
I'd go to the past postings
(see search bar at www.CARPROTECTOR.com)
and use the keywords:
starter kill fix, disarm after market alarm,
valet override, REPAIR STARTER.

Good luck.

ALARMTEK