I replaced dead battery with a new one. there is a "lock" symbol and the engine won't start. How do I unlock or reset engine?

What are you trying to say here light key on dash ? A symbol of a key light lit on the dash maybe . This would be a problem with anti-theft system .

security lockout

give me a example of a reemdem code

Very likely bad battery. Most places that sell them will install for free.

Probably one of the lock switches, the switch you push or toggle from inside the car to lock or unlock your doors has shorted. Try manipulating those switches until the clicking stops. Replace the effected switch. If the doors automatically lock when the car begins moving above a certain speed, it could be that relay has shorted.

Most models with factory alarm system can be reset by locking and unlocking the driver's door with the key.

Check the car battery there is a battery in the remote as well but its to new to need to be replaced and so is the battery in the car It sounds most likely like there is a bad connection on one of the battery terminals on the cars battery if the bat is dead in the car the remote won;t work and if the bat is dead in the remote it won;t work but the car will hope this helps

It sounds like you may a faulty door lock switch. If you pushed the switch to lock the doors and the switch stuck and kept door lock solenoids energized, that would drain the battery. It would also keep the door locks from unlocking, as to why window don't work it could all be on the same fuse or circuit breaker. Usually the power windows are on an automatic reset circuit breaker. Do you hear click and a short time later another click (with the battery charged)? If so that the circuit breaker tripping then resetting. Good luck!

The factory security light will remain on - this is a standard feature indicating the car is dead.
First, unplug the hazard fuze in the engine bay (this will reset the ecu and remove the flashing)

Next, replace the battery with a new one (or one with proper charge) - keep in mind a small battery will not do anything for these cars, the engines require a lot to push them over (it isnt a honda)
*Make sure to clean the positive and negative battery cables from acid

Then just start it up :)

so my 06 cobalt keeps dieing and i have to jump it alot lately is it my alt or my battery