When trying to start and wont turn over, car keeps trying to start after key off and key pulled out!!! starter???????? how hard is a starter to replace on 2000 corolla?

first make sure battery is charged if so then then check the relay in the fuse box under the hood find the relay that marked "ing" pull that relay then find a nother one to inter change with it, if car still wont start then ou will need to see if the in line fuse on the starter wire is good or blown if its good then you will need to pull the starter and replace it. hope this helps you

There is a spring which may be weakened or broken that retracts the gear. Only a service will fix.

I would bet the ignition starter switch is defective, but your description is very vague and that is a guess.

the clicking noise is usually 2 things, step on try jump starting car and if starts have battery tested as it is probably bad (free testing at most chain auto stores), the other usual problem is that the starter has gone bad, when whoever tried turning off car while driving might have put into start mode and burnt out the starter when it engaged at high speed.

Could be your starter, sounds like your starter soloinoid(pulls starter gear into flywheel) might be defective. First it will not pull gear in, then if it sticks in your car could keep starting even if the key was turned off .
without looking at the car I could'nt say how hard it would be to change. It has been my observation that newer cars are much more difficult to change

the starter relay isn't that hard to replace, and is probably your problem. If you can remove the starter and take it to autozone or similar, they can probably test it for you.

starter switch maybe loose

sounds like you have a bad starter. If you can see the starter have someone bang on it while you turn the key. it might start. if it does you still need to replace the starter. Make sure the cables going to the starter are clean and tight.

try tapping on starter while someone truns key, sounds like bad starter if wires are clean and tight. good luck.

Pull the starter out and bring it in to the auto parts store to get it tested