Originally Posted by
Mr869 Press and hold the power and home buttons. Keep holding past the " power off" screen until apple logo appears. It is a soft reset.
Just to clarify... you'll see the red "slide to power off" slider if you just hold the "sleep/wake" button on the top of the iPhone, and if you activate that slider your iPhone will power down. Then you hold the same button to power it back on.
If you hold the top "sleep/wake" button and the round "home" button at the same time after a few seconds your screen will go blank and then you will see the Apple logo -- this is a reset.
Neither of these actions will delete or reset your data or settings.
Restart iPhone via Apple