The iPhone is much more than a ‘phone’, or even a ‘smartphone’. As with several other phones on the market, the iPhone is really a really small computer. It has a operating system that allows you to do many things; access a camera and take photos, arrange data like contacts and dates, and install applications.
As time goes by, opening and closing applications (even just the applications that came pre loaded from Apple) bits of data and parts of programs start gumming things up. What you need to do is what you do to your notebook or desktop computer. You need to shut it completely off and restart it. Like almost all computers, you can do this with your iPhone without loosing any information (games will still know your score and your calendar will all be fine, etc…)
Restarting your iPhone is very similar to taking a picture. But instead of holding down one button and tapping the other – to restart you push both of the hardware buttons. One on the front of your iPhone (the ‘Home’ button – has a square in the middle but no other label) and the button on the top at the same time. And hold those buttons down.
After a few seconds, the screen on your iPhone will go blank and just have a slider image near the top. You now release the buttons and slide the image across the screen (under the image is text telling you to slide to shut your phone off). Once you slide it from left to right, the screen will come up with a spinning icon for a few seconds then go blank.
To start your iPhone back up, press the button on the top for a second and release. A white Apple log will appear while the systems starts back up and then go away leaving your normal screen showing.
If you ever happen to see that slider on the screen and you didn’t want to restart your iPhone, follow the instructions on the screen to abort the shut down. This could happen if you are taking your phone out of your bag/pocket and happen to hold the two buttons down at the same time.