IPhone 4s not playing music?

I had like 300 purchased songs on my phone and today I backed up my phone and fixed some MMS settings (I have a factory unlocked phone) and ever since then whenever I try to play a song it will just continue to skip to the next one and so one. I tried to download all the songs on my computer from my itunes account and put them back on my phone but it still doesn't work?

Will unlocking an iphone 4s increase its value?

Or should I restore it? (ATT) 16 gb

Added (1). I'm planning on selling it on ebay. I have two phones, and this one was only used for a couple weeks including earphones, and an otterbox deffender with it

How much should I sell my iphone 4s for? - 2

At&t, 16 gb, white. Used for a month, the entire time I have had it, it has been in an otterbox defender series case, So no cosmetic wear/scratches. What do you think I could sell it for? I was thinking $250? More or less?

Added (1). Sorry I'm a college student. Not just giving away a perfectly good working smart phone.

Reasonable Price for iphone 4s?

At&t, 16 gb, white. Used for a month, the entire time I have had it, it has been in an otterbox defender series case, So no cosmetic wear/scratches. What do you think I could sell it for? I was thinking $250?

Added (1). Dang, people pay a lot more than that on ebay, i was looking at prices on Craigslist, but I'm going to stick it on Ebay.

If i restore my iphone to its factory settings, can i restore it again to its backup?

I have an iphone 5 and i recently bought an album off of itunes. I also then made a new icloud and deleted the old icloud account because of some troubles i had. After that, none of my music played so i hooked it up to itunes and then i worked perfectly except one thing: a duplicate song. This song will not let me play it nor let me delete it manually. On itunes it only shows up as one song. It always skips it. Now i have the same song on there, one works and one doesn't. I tried so many things including restoring it to its backup. I also looked up stuff on apple support and i'm not the only one. I'm considering just restoring my phone to its factory settings just to get rid of it. If i do this will i be able to restore it again to its backup?

Please help me, i'm getting really frustrated and annoyed.

Will apple still cover me with their 1 year apple warranty?

My uncle gave me his iPhone 4S as a gift, it has warranty until November 2013 and for some reason the phone turns off by itself about every 3 hours! The phone does not have any water damage as the water indicators are white, will apple still cover me on fixing it or giving me another one since I'm not the original owner but the phone is still under their warranty!

Is NHL game center worth buying?

Does anybody have it? It costs $4.95 a month. Is it actually as good as it looks?

- Watch up to 40 live games every week.
- Post game replays/highlights
- Watch repeats of historic games
- Rewind/restart/pause/slow motion
- Radio
- Chat with other fans without leaving the game screen
- Multi-game views (you can watch like 4 games in 4 corners on your screen at once)
- Can be watched on Computer, iPad, iPhone, Android, PS3, Xbox 360, Boxee, Apple TV, Roku, Sony Devices)

Added (1). Oh nevermind $4.95 is for if you're not watching games live. I don't know how much it costs for live