Any ideas on what could be wrong with my car? - 1

I own a 2008 Honda Civic. When I returned home after driving around for a while I turned my car off but once outside of the car it sounded as though it was still running. I tried turning my car on and turning it back off, but the sound continued. I left it thinking it would be okay. The next night I tried turning my car on it is completely dead. Any help on what it could be?

If you left your car running overnight then it probably ran out of gas and if the lights, ignition and all that were left on it also drained your battery. So, at the very least you have a dead battery now.

You probably have an ignition problem if you can't turn the car off. If you eventually do get the car back up and running and need to turn it off, switch the key to off while in gear with emergency brake on. The reverse torque should stall the engine. In any event, you need to bring it to an auto tech right away.

Hi what is known as pre-ignition what we would have caused the needs for a de-coke.