How to Put the iPhone, iPad and iPod touch into Recovery Mode

If your iOS device is not being recognized by iTunes then you may need to perform a recovery-mode restore.

Please note that you will lose all the data on your iPhone when you restore it, so this should be used only in the worse case situation. However, If you’ve taken a back up of your device using iTunes or iCloud, you will be able to restore from the backup.

Please follow these instructions to perform a recovery-mode restore:

• Connect your USB cable to your computer but not to the iPhone, iPad, or iPod touch.
• Turn off the device: Press and hold the Sleep/Wake (Power) button for a few seconds until the red slider appears, then slide the slider. Wait for the device to turn off.
• If you cannot turn off the device using the slider, press and hold the Sleep/Wake and Home buttons at the same time. When the device turns off, release the Sleep/Wake and Home buttons.
• Now while pressing and holding the Home button down, connect the USB cable to the iPhone, iPad, or iPod touch. The device should turn on.
• Continue holding the Home button until you see the Connect to iTunes screen. When this screen appears, you can release the Home button:

• Note: If the image of a battery appears, let the device charge for at least ten minutes to ensure that the battery has some charge, and then start with step 2 again. If you don’t see the Connect to iTunes screen, try these steps 1 through 4 again.
• iTunes will launch automatically inform you that your device is in recovery mode and that you need to restore the device:

• Note: If iTunes not open after two minutes, please open iTunes yourself. 
• Click on the “Ok” button and then click on “Restore” button to restore the device.
• After the device has been restore, follow the on-screen instructions to set it up, and recover from the backup.

You can also check out the video walkthrough of the entire process:

Please let us know how it goes, and please feel free to leave a comment if you’ve any questions.

Source : iphonehacks