phone doesn't start just hear initial boot sound

When I try to turn on my iphone nothing comes on the screen but I hear it trying to turn on. This repeats every 10 seconds, I hear it trying to turn on.

does this indicate battery problem?

Full Story. Sorry for the piecemeal.

It all started with the main camera was not working. Brought it in to the apple store and they reset the phone to see if it would help. It didn't help. They wanted to replace the camera and the camera board. I didn't want to spend $300. After that the display starting to act funny. I opened up the phone to make sure the connections were secure. Now the phone display is blank..

It only makes the sound when it is plugged into a power source. iTunes recognizes the iPhone. I can't backup because I can't type the password on the iPhone since the screen is blank.