Occasionally your iPhone may freeze or hang during an operation - old timers would call it a crash - and won't respond to the home buttons, sleep button or the touchscreen.

If this happens there are two solutions you should try first:

• Option 1: press and hold down the Home button on the front of the iPhone for at least 6 seconds. In most cases this should shut down the unresponsive application and return you to the main menu
• Option 2: if option 1 didn't work then you will need to reset the iPhone. You can do this by pressing the Home button and the Sleep/Wake button on the top the iPhone's case and holding them down together for 10 seconds. The iPhone should then reset itself and return to the locked state

If neither of these two options fixes your unresponsive iPhone then you should connect it to your Mac or PC and launch iTunes. Click on the Summary tab and then click on the Restore button.

This will restore your iPhone to its factory settings and install the latest version of the iPhone operating software. It will also erase all the songs, videos, calendar and contact information on the iPhone. (Though it is easy enough to reinstall that info by syncing with iTunes when the iPhone is fixed).

If none of the above methods fixes your iPhone you will need to call the retailer who supplied it to you.