My iphone screen went black, but the phone is still working?

I was using my phone all day long and it was working perfectly. Then all of a sudden the screen went black and I thought the screen just dimmed down, so I hit the lock button but it stayed that way. Every once in a while it would light up for like one second when i got a text, but then go black again. My sound still works and everything just the screen is black. What can i do?

IPhone 4s with AT&T can't access certain apps on cellular data?

I have an iPhone 4s on AT&T, about 2 years old, and just this last week I have lost the ability to connect to facebook, snapchat, and some other apps when I'm on my cellular data. Safari and google app still work on cellular data, but some other problems exist, such as that my recent calls have not been updated since the problem started. I've reset network settings and tried a few other little things in the settings app based on advice online, but nothing has resolved the issue. Also, recently I downloaded a gameboy emulator on my phone without jailbreaking it, and I don't know if this has affected it in any way. Apple then disabled the emulator on the 16th of July (I think), but I was able to restore it without any problems by turning off my automatic date/time check and setting the time back a few weeks, since the "signature" the app was using was still relevant before that time (as you can tell I'm not a real techy, I read this online as well).
Thanks!

Added (1). Samantha. I guess I should have also mentioned this. I took it to my local AT&T store and the salesman said that there was nothing they could do, but that if I took it to an Apple store they would be able to shutdown and restart my apple account, which has fixed some people's phones with (I guess) similar problems. He sort of suggested that the issue might be that I'm logged in to my itunes on a foreign device, but I know for a fact that I haven't logged in anywhere but my own laptop in the last few weeks

Should I start nail tutorials on you tube?

I was thinking of starting an account for my nail designs, I'm always complemented on them and its my favourite past time. I just have a few questions
1. Long or short tutorials?
2. What should I name it?
3. How can I promote it?
4. I'm planning to use my iPhone 5 as a camera, how should I set this up and does anyone have any ideas of movie making software to use?
Thank you so much for all your answers! Much appreciated!
Harri x

How to browse iphones apps on iphone without appstore, i mean online site?

Actually all i wanna know is dat does Adobe Photoshop Touch works on iPhone 3gs?
N is der any way to view full app info online without openin Appstore
D apps on dis site iphonecake.com/appcake
Shows app n when app logo is clicked a apple itunes site is opened with full info of dat app(only on PC)
So if you r on pc please tell me dat link assm on mob
Nothgz workin

Trading my phone and laptop for iphone?

I have been offered to swap my phone (htc desire z with 32gb sd card) and my laptop (toshiba l450-16q) for a iphone 3gs 32gb but on my laptop the f7 key is missing and my htc Wi-Fi won't connect to Wi-Fi but at the same shop for £50 more i can get a iphone 4 32gb so should i ask for that instead for what i'm giving?

Where can I get my iPhone repaired under $50?

I'm constantly worried about my iPhone 5 breaking. I love this phone so much because it can do so much and is so high quality. I can't afford to repair it for hundreds of dollars. Is there a place I can go or send my iPhone 5 to be repaired or replaced possibly under $50? If not.under $80 maybe?

Is my iphone dead? The white screen of death

I have an iPhone 3gs. (I know! How outdated am I?) and well I dropped it yesterday. It was fine then and i used it for several hours afterwards but this morning when I woke up, the screen was blue. And then it turned black. I'd hit it against my palm and it'd become normal again but touch the home button and BAM! Black again. And I guess I hit it too many times coz my palms red and the screen's white now. It's weird coz if you call my phone it's still ringing and the screen lights up, but I can't do anything other than that. Rebooting didn't help.
can I do something to fix it? Is it dead forever. (please don't say yes:/) all help will be appreciated.