Connect your iPhone to your computer
First of all you need to connect your iPhone to your computer by the USB cable. Attach the USB cable in the port at the bottom of your iPhone. Attach the other end of your cable to any of the USB ports in your computer.
Remember to plug in the cables in right directions and calmly.
After connecting the USB cable with your iPhone and computer, launch iTunes. You may not need to manually launch iTunes as when you connect, iTunes will automatically load.
Restore your iPhone to its original settings
Next you need to restore your iPhone to its original settings. You can do this by clicking ‘Restore to Factory Settings’ on the main menu. This process removes all your date, media files, contacts etc from your iPhone. Bootloader is also automatically removed from your phone.
Once the restoration process is completed, iTunes adds your main iPhone products back into your device.
Note that this process requires several minutes and you need to be patient. Also do not do any other task in your computer or in your iPhone during the restoration. You will also be not able to receive any calls or messages during this process.
In case you have precious data, media files, photos or contacts in your iPhone, its better you save them in another computer’s hard disk or any other storage devices. You should make a back up of your things as during restoring process, your phone unintentionally removes some of your files.
Unplug your iPhone
After restoring your iPhone to its factory settings, click the ‘Eject’ button on the main menu. This button is listed on the left side of the iTunes programme. After clicking the button, you will receive a message that you can now safely remove your mobile. Then unplug your USB cable from your phone and computers.