Is your iPhone sluggish & lacks memory to run certain application? You can restart your iphone by the following

1. Press & hold Sleep/Wake button until “slide to power off” appears
2. Slide & power off
3. Press & hold Sleep/Wake button until apple logo appears
4. wait for about 2 minutes for iPhone to reboot (be patient)
5. iPhone should run faster

What if your iPhone simply hangs and freezes up which you cannot “slide to power off”? Simply hard reset your iPhone by

1. Press & Hold both Sleep/Wake & Home button for 10 seconds
2. it should flashes & reboot with apple logo appearing
3. wait for at least 3 whole minutes to boot up.