You need to do a DFU Restore,
1. Connect the device to your computer
2. Shut down the device
3. Press the Power and the Home buttons at the same time
4. After 10 seconds release the Power button but continue holding the Home button
until you see a popup from iTunes saying "iTunes has detected an iPhone in recovery mode"
5. If you have been successful your device screen will be completely black/blank (this is 'DFU Mode')
6. You can now proceed and restore to the latest firmware using iTunes
This should fix your problem
Something else must have happened to it. What you should do is plug it into your computer, hold down the power and home button and as soon as the screen goes black just hold down the home button for up to 30 seconds, your itunes should finally give you a message and enter restore mode where you can update through itunes and fix any software issues that might be causing this glitch...
I was having a very similar problem with my ipod classic a few months back. I had no idea what the problem was and nothing really seemed to be making sense. After some extensive testing and switching out of parts, I found out that it was the hard drive cable that was causing my ipod to continuously restart itself. I think the problem occurred because I left my ipod in my car for a few days and it got excessively hot in there. I imagine your problem is something similar to this.
I have a son who decided to jump in the pool with his iphone 4 in his pocked. He put it in the rice for a few days and the phone turned on, but it would not charge past 4% and it kept shutting down after a few minutes. I managed to do a backup in itunes, because it will resume after the phone restarts and starts up again (you have to have a lot of patients for this) but it would not restore anything because it kept restarting. Well I ordered a new battery from ipod Battery Depot for $22.94 plus shipping of $5.96, I installed the battery then went into itunes and did a restore from backup and everythings works great now. I am a 69 year old lady, and if I can do it anybody can. Good luck.
Oh boy this could be a number of issues. I would have to start this with some questions.
What model is it?
Does it hold or show a full charge before restarting or on home screen?
Does it restart back to the home screen? Lock screen? Apple or iTunes logo?
When you plug it in does it show the battery charging or blinking?
Does it reboot only when the charger is plug in or before?
Must you leave it plugged in to function?
Based off the comments above, I would say it is one of 3 thing.
-You need a new battery which is not uncommon for iPhone 5 and below.
-You have a little bit of water damage on the logic board.
-You have a Jammed power button.
-I would normally say charger port to, but you said it was recognizing the charger.
Please send me some answers, I am happy to help!
using a flashlight, inspect the dock connector and headphone jack. There are liquid immersion indicators in both areas, which will turn pink/red if the device has been exposed to excessive moisture. Also look for greenish corrosion on the dock connector pins.
If the battery was the only issue, it would at least give you a low battery indication when connect to power.
If the immersion indicators are still white, try cleaning the dock connector of debris with a SOFT toothbrush and a little compressed air.
I would try restoring the phone in recovery mode. This will not allow you to make a backup, so anything you are not up to date on will be lost. iPhones don't store contacts on the SIM card. They store it in the internal memory.
To do this, plug your phone into a USB port. Then press the power and home button at the same time to reset the phone. Once this is done and at the Apple screen let go of the power button and keep holding the home button. The phone will be in recovery mode.
I don't think you guys are reading the previous post before you put your suggestions up, you cannot restore a phone if it is not showing up on the computer unless you know something I don't and I am willing to learn so if there is way to get the phone to see the phone that I haven't tried as yet please let me know.
woohooo - who dug that up ?? ;-)
one question to mortenskogly - are you hagar24 ??
(only to figure your initial problem out)
so i try to pick up the pieces and also try to understand the problem:
the phone was longer not in use and when you tried to charge it - it restarted always - thats a typical charging problem: the usb gives only enough power that the phone could start - but not enough to fully boot up, so the battery die within the boot process and the whole problem starts again - this happend with maaaaaany motorola phones in the past - i used a aa battery emergency charger to help normal phones to skip this point and the were able to normally charge within 1h
but the iPhone is different - there is no normal "emergency charger" for it - so i desolder the battery and charge it external, resolder it and everything works.
restore didn't work
did you tried different software versions for the restoring ?
what software did you have had and what did you try to install ?
there are some "solutions" for the 16xx errors - one that i never tried is this - maybe i should try it on my error 1604/1601 iPod touch
As you stated the phone has been sitting around, the battery has most probably completely discharged. If its still under warranty, take it to an apple store for a replacement.
If not its pretty easy to replace your battery yourself.
Or there are companies out there that will do this for you for a fairly small fee.