There may be times when you iPhone stops working, is locked and freezes or is not working just not working right. There are a number of restarting, force quitting or resetting options available to get you iPhone working again.

The iPhone also collects additional data such a custom dictionary words, network settings and location-based settings. This information can also be deleted if required.

Restart iPhone

Press and hold the Sleep/Wake button (See Image - ) until the red slider appears. Slide your finger across the slider to turn off iPhone. To turn iPhone back on, press and hold the Sleep/Wake until the Apple logo appears.

If you can't turn off iPhone or if the problem continues, you may need to reset. A reset should be done only if turning iPhone off and on doesn't resolve the problem.

Force Quit an application

If you are in an application and it freezes, you can force the application to quit. Press and hold the Sleep/Wake button (See Image - ) on top of iPhone for a few seconds until a red slider appears, and then press and hold the Home button (See Image - ) until the application quits.

Reset iPhone

If you cannot force quit and application or restart your iPhone then resetting it will normally sort everything out. Press and hold the Sleep/Wake button (See Image - ) and the Home button (See Image - ) at the same time for at least ten seconds, until the Apple logo appears.

When you reset you should not loose any of your data, however if you were entering data into an application this may be lost.

iPhone Still Doesn't Respond After Reset

If your iPhone is still not responding as expected after a reset then you can reset all of the iPhone settings.

From the Home screen choose Settings --> General --> Reset and tap "Reset All Settings". All your preferences and settings are reset. Your information, such as your contacts and calendars, media, songs and videos, aren't deleted.

Erasing All Content and Settings

You are able to erase all the data on your iPhone including all of your media and information, and to default all your iPhone settings. This is particularly useful if you are selling your iPhone. Once completed you can plug your iPhone into your computer and use iTunes to restore your data and settings if required.
 
Connect iPhone to your computer or a power adapter. Choose Settings --> General --> Reset and tap "Erase All Content and Settings."

IMPORTANT: You can't use iPhone while data is being overwritten. This can take up to two hours or more, depending on the model and storage capacity of your iPhone.

Reset Network Settings

If your iPhone is having problems with Wi-Fi or Bluetooth it may be necessary to reset the network settings. When you reset network settings, your list of previously used networks and VPN settings not installed by a configuration profile are removed. Wi-Fi is turned off and then back on, disconnecting you from any network you're on. The Wi-Fi and "Ask to Join Networks" settings are left turned on.

Choose Settings --> General --> Reset and tap "Reset Network Settings".

Reset The Keyboard Dictionary

You add words to the keyboard dictionary by rejecting words iPhone suggests as you type. Tap a word to reject the correction and add the word to the keyboard dictionary. Resetting the keyboard dictionary erases all words you've added.

Choose Settings --> General --> Reset and tap "Reset Keyboard Dictionary".

Reset the Home Screen Layout

If you wish to reset the home screen icon layout choose Settings --> General --> Reset and tap "Reset Home Screen Layout".

Reset the Location Warnings

Location warnings are the requests made by applications (such as Camera, Compass, and Maps) to use Location Services with those applications. iPhone stops presenting the warning for an application the second time you tap OK. Tap Reset Location Warnings to resume the warnings.

Choose Settings --> General --> Reset and tap "Reset Location Warnings".