passenger side works, driver side will not move at all.

which o2 sensor should be replaced? is the sensor pre-catalytic or post-catalytic

I got ran off the road into a small ditch, it didnt cause me to have to stop or check my car. It drove approximately 60 miles that day. The next day I got approximately 25-35 miles and then it started smoking and kicked or jerked then died. It started back up but only for just a moment. I cannot remember if it made a pop sound or bang. I have been asked that question before in regards to this.
When I try to turn it on the fuel pump does come on. But that's all.
Could it possibly be ANYTHING else other than the engine? Is there a way to test something, or do something or some kind of mechanics " trick " as my uncle would say. And maybe to be able to find out or diagnose the ACTUAL and ACCURATE cause or issue?
I have been reading and studying on this for 2 yrs. I dont want to junk it, because its just idiotic to do so, even if it was the engine, the car itself is perfect inside and out, no wrecks, paid off, and you can get a new engine for as little as FREE-$375 depending on who you know. Some people however would pay $1500 or so by taking it to a shop and having to pay there price for a new engine.
Anyway, its worth more than $100-$200 to me.
So while I have had so much time to just read about it, since I have not been able to come up with $375, what a salvage yard has a new engine for, I read that it may be the computer module. Or ECM? Or eccetera. Is this true?
How can I find out? Please can you help me? I thank you more than ever, so very much. Thank you.

nothing wors on my dashboard

The oil is leaking into the alternator and on the belt.

First coil pack and ignition module was used original part , it lasted about 1 to 2 wks, car would still start and run on 2 cylinders. I have been able to put this one back on to get car home to save myself a tow bill. Replaced with a new one same thing lasted about 1 to 2 wks, replaced again with a new one and same thing. Went to different shop and different brand it lasted about 6 to 8 wks. Catalytic convertor, plugs, boots was replaced.

A speaker wire was run from my stereo system to the battery and caught on fire...now my car starts, but wont stay running..my head lights come on ..but not my inside lights wont..what's wrong with my car?

So my 2004 Cavalier was of course bought used, and the previous owner said there was a pretty bad wreck with this car, and it's on a salvaged title, so I'm not expecting it to run at its absolute best. Other issues with this car I have solved quickly and cheaply. However, I've noticed that at certain points when I drive, if I'm stopped at a red light or stop sign, the car will idle pretty sporadically. It jumps from below 1000RPM to over 3000RPM, and sometimes while stopped it will just die on me and turn off. At that point, I throw the car in park or neutral, turn it off and then restart, and it starts back up with no problems. But the high idle happens when I stop or even just as I start the car. Being that I am a female, mechanics like to think they can take advantage of me so I like to get all the opinions I can. Someone suggested it was probably the TPS "throttle position sensor" or the EIC "engine idle control". I was wondering if others have had this problem and that is what it turned out to be??