Why does my iPhone screen go away when it turns off and back on?

When my AT> 64gb iPhone 4s turns off, or dies, for some reason when I try to turn it back on, the phone itself turns on but the screen doesn't. Sometimes the screen will be a bright white, sometimes it will appear as if the LCD is cracked, and sometimes its just straight black. Eventually (like up to 12-15 hours later), I somehow manage to get it turned back on like regular, and it works fine (however occasionally, there's a white circle that surrounds the middle of the screen. Anyone have any clue what's going on with it? I'd just get the LCD replaced, but it only doesn't work when the phone turns off and back on, so i don't know if that would help at all.

How to tell if my iPhone 4 can work with straight talk or even virgin mobile?

Okay so I bought this iPhone 4 from my friend yesterday. It isn't jailbroken, and I kinda don't know if jailbreaking is a good idea. Anyway, this iPhone has a SIM slot on the side. It came originally with an AT&T SIM, and worked with my old AT&T GoPhone SIM that I had cut. Now, I don't know if this feature means I can put any cell phone carrier's SIM in there and it work, or what. I'm unsure of Apple in general.lol.
If anyone could give me advice on this this would be great. I had Virgin Mobile before I bought this phone, and I'd like to stay with Virgin Mobile. I mean 35 dollars for unlimited text and web and 300 minutes of talk? I think that's pretty great and it always has worked with my budget. I don't want to use At&t because their prepaid data plans are stupid. Just stupid. My virgin mobile phone before didn't have a SIM in it, so I'd have to order a new SIM for whichever carrier I decide upon. Straight Talk is another option, too.
I just really need some advice here, Apple and I aren't too familiar, so it's quite a puzzling process for me.
I'll appreciate answers greatly.

Iphone 5s - 14 years old - girl?

Hi, I'm 14 and want to get an iphone 5s. Is it worth it? I have an old nokia, its not touch and without internett… But maybe iphone 5 would work? Or iphone 5s is MUCH better? Allsow should i get 16 GB or 32 GB? I like to download music, take a lot of pictures and vieos, i download pretty much apps, like 15… Haha maybe not so much but yeah. Can you help me to decide? I'm from Norway btw.

Added (1). I have had an Iphone 3gs before, but i had to give it to my sister… So i have an Nokia now from my grandmother therefore…

Can I use my Verizon iPhone 5 in China?

I have a Verizon iPhone 5 and I will be traveling to China in a couple of months (I live in the US) so I'm wondering if I will be able to use my phone for making calls and using apps that require the Internet if I unlock it?

How to catch my husband cheating?

Okay so i'm 60% sure there's someone on the side, he won't admit it but all signs point to it, how do i catch him in this to prove it? He deletes messages and i know it, how can i catch him. Can i go on his kik off my phone withoutt the messages being deleted? He always has his.always always.anyways… Help? Please.anything. At all. Any apps that i can download, i have an iphone so no google play apps please.

IPhone 5 sprint unlocked or carrier?

So I'm planning to buy an iPhone 5 on Craigslist, but I'm a little confused about the unlocked and carrier stuff and I want to be sure I'm buying the right phone. I looked at a phone and it said that it was a sprint phone unlocked and then I looked at another iPhone and it said it was a sprint phone not unlocked and it was a lower price. There was also a phone that was factory unlocked I think this is the phone that can be used with any carrier but I'm not sure. I'm planning to buy an iPhone with sprint prepaid card. Will it work with the sprint iPhone 5, unlocked iPhone 5, or only with a factory unlocked iPhone 5? Sorry for the long story lol I'm just really confused about this someone help thanks. Or any suggestions about getting an iPhone 5 with prepaid? Sorry I'm new to buying my own stuff. Feeling dumb…