1. Download the IOS firmware IPSW file to your desktop
2. Here is the link :
http://appldnld.apple.com/iOS7/031-1767.20131114.P3wE4/iPad2,2_7.0.4_11B554a_Restore.ipsw
3. Put your device into DFU mode.
4. Put your device into DFU mode
In order to put your device into DFU mode, with the iPad connected to your computer and turned on, you must press the "home" and "power" buttons together for EXACTLY 10 seconds at which point you must release "power" but continue to hold "home". After about 15 seconds, the device will enter DFU mode.
Once your device is in DFU mode the screen should be blank. If anything else is showing on the screen, such as the "connect to iTunes" logo, you got it wrong. You must get the device into DFU mode successfully
5. Manually restore in iTunes
Finally, you are ready to restore your device using the firmware you downloaded in Step 1.
Open iTunes and it should report that it has discovered a device in recovery mode and must restore it.
Now you must hold down the shift key (on Windows) or the option key (on OSX) on your keyboard whilst clicking the "Restore" button in iTunes with your mouse. An Explorer or Finder window will pop up and allow you to navigate to the firmware file you downloaded in Step 1. Find the file and choose it for the restore.
Done! iTunes should now restore your firmware file on your iPad without any errors.