Over the last few days, my wifes iPhone will suddenly turn off and reboot. It happens mostly when making calls, but has also happened when trying to send text or checking email. Screen goes black, the Apple logo pops up, and after a few seconds, it shows the connect to iTunes screen. From there, I can soft reset and it goes back to normal. Any ideas? I am doing a restore now, so hopefully that will solve the problem. Thanks in advance!