A Knock sensor? Out of no where my car just would not start?

Ok I have had so many problems with my Alero it aint funny. I have put so much money into it that im sick of it. I have put 2 fuel pumps in it, power steering pump, spark plug coils, ignition wires all over the past 2 years. Anyways out of no where my car just would not start. It will start for a few seconds then die, once I try it again it only turns over. I used a computer read and it says 3 O2 sensors no activity and a knock sensor. I want to know if a knock sensor can do that to your car? Im trying to fix this problem myself instead of putting it in a shop and spending hundreds of dollars yet again. So can yall help me and tell me if a knock sensor can stop a car from starting?