IPhone 4 refuses to turn on

After playing a game on my iPhone 4 I locked it for a few minutes and when I tried to unlock it, it just gave me a black screen. I tried the hard reboot (holding the lock and home buttons) and saw the Apple logo, but it wouldn't go away after a few minutes so I've tried that reboot for what feels like a thousand times, but it won't turn on.

I tried connecting it to my computer and putting it into Recovery/DFU modes, still nothing

I think I've tried every possible method I could find, and the thing just absolutely refuses to start up. Is there still hope or should I just take it to the Apple Store?

Different Apple ID shows when I try to update an app?

I was gonna update my YouTube app in the App Store on my iPhone 4S which is still iOS 6. When I click Update, it pops out a different Apple ID then what is actually mine. The Apple ID on the settings is set to mine, and also at the home page in the App Store. I don't have any idea how to fix this.

Are iphone 4 still good quality these days?

So i'm buying a second hand iphone 4, not 4s, just 4 because it's all i can afford, i was just wondering a few things. Are they as quick as 4s/5 like with apps and whatnot and is it ios7 compatible? Like does it offer all the same quality in speed and holding data and stuff or does it get slow easily/appear to be slower than newer versions?

ALSO is the camera quality any good compared to later versions? Like does it have a decent front cam and back cam/cam zoom? Basically is it a decent enough iphone for 2014? Haha thanks.

How to purchase a free app on my IPhone without having to use a credit or debit card?

I recently tried purchasing a free app and it told me I had to update my card info due to the fact that my last purchase over Drew my account. So it wants me to add another card. Well first of all I shouldn't need a card to purchase a free app, and secondly when I first got the phone I downloaded a lot of free apps and I had no card on file. I only put the card on a couple of months ago to buy a song. Anyways, is there anyway around this or anything I can do to the phone?

How to get started creating a iphone app?

So i really wanna learn how to create a app before doing one. Where is the best website to learn how to build a app? And i checked the apple website to download Xcode 5 but my concern is can they steal away your app that you created? What if its a genius app that you created but apple stole it from you?

Why does everyone like Apple?

It seems like everyone has an iPhone or iPod. Apple isn't a very good company. So why does everyone ONLY buy Apple products?

Can I use my Sprint iPhone 4s on T-Mobile?

My contract with Sprint already expired. What I want to know if there's a way to use my iPhone with T-Mobile. Now I already understand that they use different technology, but my Sprint phone has a SIM card slot in it with a Sprint SIM inside. So if I unlock it could I put a T-Mobile SIM in it and use it with their service?

IPhone 4 - still good phone?

I'm currently in the process of leaving Verizon and switching to a non-contract place, Virgin Mobile. I'm trying to find a phone with a *good* camera, as I'm constantly taking pictures, and one with all of the necessary updates to have it function 100%, of course.
I have been using Android ever since I got a smartphone and am thinking of switching to the iPhone because I know it's reliable and is one of the better phones Virgin Mobile has.
My question is, can I get an iPhone 4 and still be happy with it even though the 5 is out? The 4 is only $160 compared to the 5C's $350. Is a brand new 4 going to run well and have the latest iOS and all that, or is it all but mandatory that I go to the 5?