My 1999 vectra Diesal does not start?

my 1999 vectra does not start at all, the engine cranks over but does not start.

I have done a full service changed battery and no luck. I have been told it could be the diesal pump or the lifting pump in the fuel tank.

Firstly, could anyone suggest what it could be? secondly how do I determine if its the diesal pump or lifting pump?