I have a vehicle Nissan Largo with immobiliser problem?

I have a vehicle Nissan Largo 7 seaters, when turn on the ignition key nothing happens only the lights on the dashboard will come on and the vehicle will not crank or make any sound, people suggested that it is likely that the vehicle has immobiliser fitted but I only got a key to the ignition without any fob. How do i solve this problem please.

James