Why wont my vectra start?it will catch but wont turn over,its a 04.i drove it 50 miles it was smooth,stooped for an hour got bk in and it wouldnt start,tryd jump starting it,wouldnt work,a mechanic came and put fuel pump in it and still wouldnt go,tryd spare key still nothing.no errors came on the diagnostic test,all lights working fine when the key is in the ignition,plz help me,b4 i spend any more money