worn ignition switch
Have the ignition madule checked out.
Check your motor and tranny mounts to make sure everything is tight and not moving the transmission. Also check vehicle speed sensor.
there might be a bubble in your radiator
Bad thermostat, plugged or damaged radiator, loss of coolant, ignition timing is off, faulty water pump, head gasket... and who knows what other problems can cause overheating.
you might need a new ignition
Did you reconnect the batt.? The computer might need to be reset. Push it to start it once and things might go back to normal.
Ignition might work.
if the car is a 2.0 the ignition coil is located under the top of the intake manifold sitting between the valve cover.It is sitting right on the inside of the intake manifold.there is three bolts to take off and you have to on plug it.Sorry my description is probally bad.hope it helps.on a 1.8 the coil isn't replaceable because its built into the distributor you might have to replace the whole thing.I not to sure i could be possibly wrong.
The battery might be dead, or your engine might not work. *EDIT* Check your ignition coil, or starter solenoid, instead of saying "your engine might not work". If you take a hammer and tap the starter when somebody else is cranking the vehicle then you need a new starter.
If the security light is flashing you need to change the ignition switch it self. It is likely worn out.
The engine may experience spark knock AKA ping or pre-ignition. Excessive pre-ignition can cause damage to engine if allowed to continue.
The ignition system and the fuel system usually get their power form the same location. You might have accidentally removed the power form the ignition system.