Car wont star

As long as the strength of the antifreeze is still at least -20 degrees, I wouldn't change it.The problem with flushing a coolant system and putting in new coolant is has a strong acid base and will start to eat at old freeze plugs in the engine,starting them to rust faster and then leaking your new coolant. You will be using Green antifreeze, not orange or yellow.

Not turning over is an electrical problem.

Well it could be a problem with the fan relay, or it could be a safety feature of the computer.
if the computer finds a problem with the cooling fan or the engine temp sensor, it will turn on the fan to try to prevent overheating. Even if the engine is cold.
If the check engine light is not staying on, I would check the fan relay for power and ground.

rite on the shift console you should have a hole or a key hole witch ever you have put your key in it and you will be able to put your car in park

If it is turning over but not starting, I would put it in a warm garage and let it thaw out for awhile or out gasline antifreeze in the gas tank and let sit for couple of hours turning the key on periodically to pump gas into libes with the deicer because it sounds like a frozen gas line. Let me know if we need to go further

Sounds like the starter solenoid has had it.

Change out ignition moduel, tighten all grounds.

are you getting spark? check that

Check to see if your getting spark. Pull one plug whire at a time. with plug in wire. resting on engine (not holding) have someone turn the car over look for spark.

If you have spark in all cylinders. Also check to see if your getting gas.

Check ignition switch as these have been issue for me in the past. Use multimeter and test switch

If headlight do not come on, leave them on and start check ground and power.
If headlights do come on then locate the starter and fine something to tape on it, not too hard,
but before u can do this have someone set inside the car with the key turn in the start position...

Anthony