how to open my old apple id

I reboot my iPhone 5 and now I can't restart the iPhone because he is blocked,

my iPhone 5 is connected to the program "find my iPhone".

The system ask me to in to my old apple id and to disconnected from "find my iPhone".

My problem is that I don't remember my old apple id (h...........@icloud.com),
when I buy my new iPhone 6 I change the apple id and my email address in apple website.

Please tell me what to do to restart my iPhone 5 ?, I need him for my daughter.

how I get my first apple id, the password and the email I wrote when I open my first apple id?

thanks' a lot for your support