My iPhone 4s keeps rebooting. Please Help

Ok i have has this issue a few times, unfortunately the only fix i have had was to force restore the iphone, if your happy to do this you will loose all the data on there, but most things will be stored in icloud.

Do a hard reboot holding both the sleep/wake key and ho,e key until the phone turns off then release (usually you would wait until you see the apple logo but we need the phone off) then turn on your laptop or PC/Mac and open itunes, plug the USB cable into your laptop or PC/Mac and then whilst holding down the home key solidly plug the cable into the phone wait a short while and you should see the connect to itunes icon on the phone, itunes will prompt you that it has detected an iphone in recoverery mode and will download the latest version of iOS once downloaded it will install onto your phone and it should be working as normal, usually i set up as a new iphone just incase it was something on the phone which caused the problem in the first place.

Sign into icloud and you can just redownload your apps etc and sync your music, let me know if this helps at all and good luck.

i have the same problem and can`t do that because in the restore process time, my iphone restarts, and itunes displays error 9 or -1