2001 Nissan Almera 1.5 Petrol will not start?

My Nissan Almera 1.5 Petrol hatch will not start following a fuel pump change (previously identified by diagnostics as a problem) - all fuses and relays have been checked and the battery has also been changed. When the key is turned there is no sound indicating the pump is being primed and if the radio is on it shows WAIT then eventually SECURE. The immobiliser light is no longer visible at any time (key in or out). Had another diagnostics attempted but it would not even register a reading. The engine turns but will not start; suspect the immobiliser but would appreciate some advice and help in what else it could be or what to check.