Samsung Galaxy S4 will not turn on?

[AC Question]

My samsung Galaxy S4 can charge fine, make noises fine, etc. But it will not turn on completely. I have t-mobile as my carrier and whenever you turn it on it loads and has the white background and pink "t-mobile" logo that is loading. My samsung just continues to load. I've tried rebooting it, but it say's an error occurs. I don't know what to do. please help! Thanks in advance.