1997 volvo changing battery

Howdy,
I just changed the battery in the 1997 960 volvo and the car will not
start. The lights come on inside the car. I found the code for the
radio to work however when I turn the key to the start position the car
will not turn over; however the alarm starts to honk the horn. Is there
a code or switch I need to know?

 

I think the imobilizer comes on by default , you have to turn the alarm
on and off to reset it, or if it has a service key, (my 440 is in the
back of the glove box) then you can turn off the alarm etc and turn it
on when all is settled

 

In <>,

That's happened to me once (with an 850). Here's what I did. Got
out of the car and locked it using the key (not the remote). Unlocked
the car using the key, and started it up. Worked fine from that
point on.

AC