iPhone doesn't turn on

[juliagh1]

Hi there! So my question is regarding iPhone 4. Last Monday I had my cellphone with me and suddenly it turned off. I remembered it being charged. Still, I went running to grab the charger and plugged my iPhone to an outlet. When I pressed the power button, the apple logo appeared and then it asked for my security password. So, I dialed my security password and the device asked me to "Connect to iTunes". I unplugged my iPhone and suddenly it turned off again. I tried connecting my device to iTunes as it asked before and when I connected it to my laptop, the logo appeared as if it were turning on but it disappeared after 10 secs and it continued doing the same thing over and over. My question is basically, what can I do?

 

[eddieg]

Hard reset.

 

[juliagh1]

I tried that out but doesn't work.