iPhone 5c won't turn on

I have a iPhone 5c which has the sleep button not working because for some reason the circuit was torn off from the lock button (everything else worked perfectly). So I bought a circuit in attempt to fix it. Half way through I decided that I'm not gonna fix it because I could not get the battery off the phone and I got fed up of all the small parts so I assemled everything back together.

However the problem is now I put the phone on charge, press and hold home button but the phone won't turn on. It would only vibrate every couple of mintues (when on silent) or make that beeping sound every couple of minutes (like it was waterdamaged?). What could be the problem?

Could it be a problem cause when reconnecting the screen?

Before anyone suggests, I can't take the phone for warranty because 1. it is now broken and 2. device was bought from another country so it did not apply to my country!