See Here > http://support.apple.com/kb/HT1808
You may need to try this More than Once... Be sure to Follow ALL the Steps...
Take your time... Pay particular attention to Steps 3 and 4.
After you have Recovered your Device...
Re-Sync your Content or Restore from the most recent Backup...
Restore from Backup > http://support.apple.com/kb/ht1766
Make sure you have the Latest Version of iTunes (v11.1.5) Installed on your computer
- iTunes free download from www.itunes.com/download
FORCE IPAD INTO RECOVERY MODE
1. Turn off iPad
2. Turn on computer and launch iTunes (make sure you have the latest version of iTune)
3. Plug USB cable into computer's USB port
4. Hold Home button down and plug the other end of cable into docking port.
DO NOT RELEASE BUTTON until you see picture of iTunes and plug
5. Release Home button.
6. iTunes has detected iPad in recovery mode. You must restore this iPad before it can be used with iTunes.
7. Select "Restore iPad"...
1. Data will be lost if you do not have backup
2. If you did not do step 4 properly, start all over again.