What does it mean when your iphone screen flashes blue?

I had hust gotten my iphone and started using it. The next day i was using it then i accidently dropped it. The screen was blue then the i phone turned off. I turned it on and it looks like no damage from the in or out. I don't know what this means and i'm really worried. I have only had it for two days. Can you please help! By the way i have a iphone 4s.

Take it to Apple and see if they can replace it. Don't mention that you dropped it. If they don't replace it, try removing the SIM card when the blue screen flashes and insert it back in.