IPhone problems sprint to at&t?

I got a brand new iPhone 5c I bought off a women and the problem is its sprint I want to give it to someone as a gift but they have a contract with AT&T so can this sprint iPhone be used with AT&T some people have told me yes and some said no so i don't know if I should just sell it or keep it or what please help!

Why is Facetime keep muting?

Why does my Facetime keep muting? I've been trying to talk to my friend all night but she keeps muting and I can't hear what she saying. I've tried everything: hang up and call her again, clean out the tab, shut my iPhone off, but nothing has worked. She says she can still hear everything i'm saying though, and I don't know what to do.

Please Help ME, I'VE TRIED EVERYTHING I KNOW!

Added (1). I know she isn't muting herself, because I can slightly here her voice, but it's really, really, quiet and I can barely hear it.

How to change the account of disabled iphone 4s without knowing the original account?

I recently just got an iPhone 4s that was donated but was locked with a pass code and i failed too many times and is now disabled and has the message "IPhone is disabled" now i'm trying to restore the iphone but i can't do that without having the account of the original owner.Is there a way to change the account? Possibly a hacking tool or something of that sort?

Clicking screen on iPhone 5c?

Has anyone else had this problem? I've already replaced one phone because of the screen clicking, Apple claimed the screen was separating. I barely had the first phone in August till October. They replaced the phone for free under my warranty, and it's now December and I've noticed that the brand new phone is doing it as well. I have not dropped my phone, I haven't hit it against anything, I haven't sat on it, I haven't done anything to it to make the screen start clicking again. I really don't feel like driving back up to my nearest Apple store because it's two hours away and to send it in would take weeks.
I just wanna know if this is like a universal problem with the 5c's or what.

Added (1). ALSO, has anyone had this problem with the iPhone 6? Because if I have to get the phone replaced again, I'm just going to upgrade to a 6 as long as it doesn't have the same problem.

My iPhone 5s turned black and white?

My phone all the sudden went black and white, but my grey scale is not on. I turned grey scale on and off, and reset my phone and nothing happened

How to transfer music from my iphone onto cassette tapes?

I have a Tascman cassette tape Recorder, And i have music on my iphone that i would like to transfer onto a tape through my recorder. Is there a chord i should be using? Any other options? I'm iffy about just hooking up a mic and recording myipgone music into a mic. Every time i've made a tape, its been live music being recorded directly into a mic, but its different if it coming from my phone and i don't want it to be fuzzy.

Can I backup a different iPhone to a external hard drive?

My mate has smashed her screen on her iPhone and needs to back everything up so that when she claims for a new one she can recover all her files. I have my iphone backed up to my mac but I want to know if I can back her iPhone onto an external hard drive so I don't clog my mac up with her stuff. Plus she can put it all on her PC once she gets it. Hope you can help.

I have a iPhone 4 and my apps aren't working?

So my data is on and my apps say they're on almost all of them but the only problem is they aren't working when I try to open them they say turn on cellular data can anybody help me thank you very much?