My car ignition switch will not turn. Cannot put gear in neutral or any gear. Completely immobilized? Do you know what to do?

Neutral safety switch on the transmission.

Try the Brake switch , as it is an important part for the transmission to work properly

Automatic tranny? Check the neutral safety switch that only allows you to turn engine on when car is in neutral. If that switch/relay is malfunctioning it could turn off the ignition when you put gearshift into gear.

Foxwell NT630 AutoMaster Pro ABS Airbag Reset Tool

Check to see if the car has oil in it. Open the hood and check your oil dipstick. Lack of oil could cause the vehicle to seize.
Look on the dashboard for a security or key-shaped light. This light represents the immobilizer, which allows the car to run only if the correct key is inserted. If this light is present, there could be a problem with the immobilizer or the key. Use a spare key or get another key from the dealer.
Put the gear shifter in neutral and try to start the car. If the vehicle turns over, the safety neutral shift could be bad. The neutral safety shift allows the vehicle to start when in neutral or park. If the vehicle turns over in neutral but not in park, the switch could be bad.
Turn the car key in the ignition to see if it cranks. If it does not crank, go to step six. If it cranks but does not start, then the problem is either spark or fuel. This means it is not getting gas, which could be the result of a faulty fuel pump or clogged fuel filter, or spark, which could result from problems in the ignition system, such as bad spark plugs, bad wires or a bad distributor cap, rotor or ignition module. If it is an electronic ignition and there is no distributor cap, the coil pack could be bad.
Turn the car key again and listen for the fuel pump to come on. You should hear the fuel pump build up pressure. If not, you might need a new fuel pump.
Put the car firmly in park. Turn the key in the ignition and if there is no crank, the electronic key pad in the ignition could be bad.
Turn the key and listen for a loud click. If you hear a click, the starter solenoid, starter cable or starter could be bad.

did you try jumping the solenoid at the starter to see if it turns?.
could be the neutral safety switch has failed or the ignition switch is bad.
1991 camrys did not come with engine immobilizers unless you have an after market alarm.

TRY ANOTHER KEY YOUR VECHICLE SHOULD HAVE 2 PROGRAM KEYS. TRY THE OTHER KEY.PUT IN IGNITION.TURN ON IGNITION SWITCH FOR 10 SECONDS UNTIL IMMOBILIZER WARNING LAMP BEGIN TO FLASH AN ACOUSTIC SIGNAL IS EMITTED.SWITCH OFF THE IGNITION SWITCH.IF THIS PROCEDURE DONT WORK.TURN KEY ON IN THE IGNITION FOR 60 SECONDS.UNTIL IMMOBILIZER WARNING LAMP FLASHES AND ACOUSTIC SIGNAL IS EMITTED. THEN TURN OFF IGNITION SWITCH.

PUT THE RIGHT KEY IN THE IGNITION SWITCH TURN IGNITION SWITCH TO ON POSITION UNTIL IMMOBILIZER WARNING LAMP ILLUMINATES FOR FEW SECONDS.KEY HAS RESET.IF IMMOBILIZER WARNING LAMP FLASHES RAPIDLY KEY DID NOT RESET.TRY TURN SWITCH ON WITH KEY UNTIL IMMOBILIZER LIGHT ILLUMINATES FEW SECONDS TURN OFF YOU READY TO GO GO GO.IF CANT RESET HONDA DEALERSHIP HAS TO USE DIAGNOSTIC EQUIPMENT TO RESET KEYS TO IMMOBILIZER MODULE.

is the starter turning?then it is a fuel or ignition problem.if there is no starter action,it could be the safety neutral switch,put it in neutral and see if it turns over.,or a dead or defective battery or connection.also,the car has an immobilizer that kills the starter.
if the key is a copy with no chip,the car will not start

you have a problem with posibly witht he adjustment on you neutral switch. the transmission has this to prevent starting in gear. it obviosly works fine in newtral so it needs to be adjusted or the lever on your transmission needs adjust ment to allow this sensor to do its job
i hope this helps

Sounds like your BRAKE PEDAL SWITCH. Have someone stand behind the car and see if the lights come one when pressed. It's a safety device in the car. You cannot go into gear unless the brake is pressed, so if the switch is bad it doesn't let the computer know to release it.