greatly need your advise....

i dont know how to explain pero it's like this....i left the car key inside the key hole coz i opened the cd dash player to get the cd. but i forgot to get the car key inside the key hole. although the car's engine is not ignited. then after 4 hours, my battery was drained. i replaced it with new battery believing it will start the engine again. but after i replaced it and ignite the engine, ayaw pa din.....

what's wrong now? is there a problem with the key system? there's no car alarm and my car is an altis.....

please help.....thanks