Probably better off with a mechanic. "Just cranks and nothing". What does that mean? I assume you mean the engine cranks but doesn't start and run, but when I make assumptions I'm usually wrong.
There can be more than one diagnostic fault code stored so just because you already know of one for one of the oxygen sensors, they should still be read to see if there's other codes related to the problem.
The oil warning light is for low oil pressure, not level. There won't be any oil pressure if the engine doesn't run so that light had better be on. That is not a clue to this problem.
The generator recharges the battery and runs the car's electrical systems when the engine is running. It has nothing to do with a no-start condition.
You already said the engine cranks so why would you be questioning the starter?
Start by having the codes read to see if there's anything related to the problem you're having. Keep in mind those codes never say to replace parts. They only indicate the circuit or system that needs further diagnosis. It is often more cost-effective to visit a mechanic, especially for those of us who install numerous parts to try to solve a problem.
Sunday, August 5th, 2012 AT 7:46 PM