Security System lites flashing & car wont start. all lites are on just wont start

If it's a GM, try a reset procedure

http://ricksfreeautorepairadvice.com/category/repair-topics/alarms-and-antitheft-systems/

What about your security system, Is there a security lamp on your dash that lites up or flashes?
If the engine starts and stalls, leave the key in the run position. If the security lamp does not flash, then the passlock system is not at fault, so says my info.

battery low?

OK. you had the battery disconnected. Here is what you do. Turn on the key. The security light will begin to flash. Wait (about 10 minutes) with the key in the ON position. The security light will stop flashing. TURN OFF the key. Then, turn on the key and start the car. Security system is supposed to prevent theft for a 10 minute delay. This usually discourages any thief. This will work, You just need to be patient with the 10 minutes. It seems like an hour when you wait ten minutes for that security light to stop flashing.

Need to turn off passlock - Chevrolet - iFixit

https://www.ifixit.com/Answers/View/.../Need+to+turn+off+passloc...

iFixitThose of you that have stalling problems, it is not passlock. ... traction fault on the display when it shuts down or won't start and have to wait my 10 min to restart.

GM Passlock Security Light Issues - RepairPal

repairpal.com/gm-passlock-security-light-issues

If you find yourself stranded, your engine won't start, and the security light is flashing, ... The most common repair is to replace the ignition lock cylinder or Passlock ... The warning light on the VATS system is similar except it does not have the ...

No Start Due to Failed Passlock Sensor : Pontiac Grand Am ...

repairpal.com > Problems > Pontiac > Grand Am

Are you using the original key? Have you tired the spare key? If you would like to bypass the VATS (vehicle anti- theft system) system fo to this link. How to bypass the VATS system in late model GM vehicle

Check factory security system

Your passkey security system is activated. The key has a transponder chip in it, if the ignition doesnt read that signal correctly, your anti theft will kick in to stop a potential car theif. Try turning the key forward like you are trying to start it. 2 clicks forward, for 10 minutes. Then turn it back and forward again and try to start. This may reset your system. If not, Its probably DEALERSHIP time.

You are going to have to get the security system reset. You will probably have to contact the dealership if you don't have the code.

CHECK for loose wires, battery cable is clean, install a new starter.