How to change apple Id on iPhone 3gs?

I've brought a second hand iPhone and I need to change the apple Id without restoring it as I know sometimes that can cause problems, anyone know how to do this it would be a great help thanks.

IPhone crashed and won't turn on?

My iPhone crashed out of nowhere. I was just on my phone when the screen turned gray and pixelated. The phone shut off on its own and restarted. Considering the phone (a 4S) has crashed before, I wasn't that surprised. However, after roughly 10-15 seconds of the apple logo showing when it was trying to restart, the apple would suddenly disappear and the screen (normally black when its turning on or restarting) might turn a slightly different shade of gray, crash again, and then try to restart once again. It did this 3 times before I managed to turn it off (trying to turn it back on produced the same result I described above).
I guess my question is, has anyone heard of this happening, is it something serious, and can my phone be fixed?
I've heard hardware failure thrown around for situations like this, but any knowledge would be appreciated.

Iphone 5, 5 months old, will it be able to be replaced?

So i bought an iPhone 5 (16gbs), 5 months ago and as soon as i got it, battery life was significantly poorer to my friends one. Her one lasted 8 hours from a full charge with heavy use everyday. My phone barely lasts 5 hours from a full charge with very minimal use. I have also noticed that the phone becomes very hot even when its in my pocket. 2 months in with my phone all of my apps started to crash regularly so i took it back to my network store and told me that i was to delete my photos because there was not enough room on my phone. There was 10gbs used of the 16gbs which i thought was quite rich. My camera also has trouble focusing. The amount of times that my apps crash is getting more frequent. I think its ridiculous to pay $1000 for a phone that hardly does its job. It is literally the worst phone i've ever had. I've had $100 phones better than this.
I also have insurance, not apple care but with my network.

Why is the iPhone 5c so expensive?

I was looking at a sim free 32gb model of the iPhone 5c, I live in Europe and checked the price of the iPhone on the us store and it was $650, which I then converted into euros to get a price of €490 which is affordable.

I then proceeded to check the European (German) store and seen that the same model was priced at €700, which then converts back to $930.

So apple are charging an extra $280 (€210) to ship to europe.

Why is this? Its not fair, this is way too expensive.

Upgrade from iphone 4s to iphone 5s?

I have an iphone 4s. My upgrade is due in mid-october, and I think I want to upgrade to the iphone 5s. Is it worth it? I've never had an iphone 5, so I don't know the major differences.

Can Iphone 5c play infinity blade 2?

Can Iphone 5c play infinity blade 2?

Added (1). NOT 5C.

the $99 budget iphone

can it play infinity blade 2 smoothly? How about iOS GAMES that it Can't play?

Added (2). I mean NOT IPHONE 5S (i'm an idiot)

I'm so sorry I kept adding details… I really don't know what I really want to ask.

anyways, is it really true that Iphone 5c will be $99? I live in the Philippines, and when it's available, is it really close to $99? Also, what does off-contract mean?

is Iphone 5c really a good phone? (note: I want an iOS device to play iOS games, but within reasonable budget)

Some kids were playing pokemon with their IPhones?

So in class these kids asked if they could play pokemon teach said no of COURSE but they did then I ask one of my friends and she said there was a gameboy app is there one and if so what is it called