Why is my iphone turning off on its own?

okayy... can anyone please help me?? Ive had my iPhone 3GS for around 18 months (it's on a 24 month contract) but recently it keeps turning itself off My iPhone isnt jail broken and I haven't even tired to jail break it as I know it will mess it up ...

My month old iPhone's screening isn't turning horizontally, why?

My iPhone 3g is not turning on. For the last couple of days it would randomly shut off out of the blue but i wouldn't be able to turn it on unless it is plugged into a wall charger. Now it won't even turn on on the charger and my computer is not recognizing...

I brought my iphone about 2 or 3 months ago off of ebay. The home button was working well then i tried to fix it then it shut down. My iphone is not coming on when i tried to plug it in,the apple logo comes on then turns off continuously. See my home...

This has happened before. Once the iPhone woke me up with Daily Show videos at 2 am. It is in a Mophie battery case and I plug the case in overnight. Last night I had made a point of force-closing all my apps before I went to sleep, but when I woke up...

They remain usable until 3-7%, then power off. But once they die, you need to charge them to ~20%. Why the difference, if they can clearly run at the lower battery level? I figure this must be intentionally done by Apple, but why? What purpose does it...

It's a fairly new phone, but ever since my siblings sent me the "Effective power" message a few weeks ago, my phone has been turning off and back on again at random times. How do I fix this?

Hey some times I'll be playing on my iPhone when the mic cuts out even if I plug in my head phones it won't work but if I turn it of and on again it works fine have u got any ideas y this is happening thanks

Iphone 4 was running very slowly so i did a hard reset and now its been almost an hour later and its stuck on the apple logo