Can someone please tell me why my car will not start?

Make story short. Got into minor accident. Car was running perfectly fine until I turned off the car engine. Car wont start. Tried jumping car, no good. No crank, just a single click from starter. I can hear the fuel pump sending fuel. The security light is on. When key is in the on position, security lights flashes every two seconds. Does the security light automatically come on when key is in the on position? Tired using obd 2 tester but it says the car is fine. No codes read. Can this be a grounding issue caused by the accident? Maybe starter may have failed due to the impact. I have a 2000 Chevrolet Impala 3.8.