To see if you have backups in iTunes, go to the iTunes menu and chose Preferences. Look under the Devices tab. It should show you a list of all devices backups on that computer, with the choice of deleting them.
Here's something that should help: http://www.ipadforums.net/threads/when-youre-locked-out-of-your-ipad.122765/I forgot my pass code. How can i retrieve my pass code?