For MAC:
1) Just go to the directory, /Users/[username]/Library/Application Support/MobileSync, and you will see a folder called Backup.
2) Enter Time machine, and replace your backup folder with the most recent one from a time when all was well
3) go to your iPhone in iTunes, right click on it and select restore from backup...
For PC:
1) Save off the backup files as a copy somewhere
2) Connect your iPhone to the computer, but don't sync, cancel it if it starts automatically.
3) go to your iPhone in iTunes, right click on it and select restore from backup...
-- see http://www.maciverse.com/restore-your-old-iphone-backups.html
2) Enter Time machine, and replace your backup folder with the most recent one from a time when all was well
3) go to your iPhone in iTunes, right click on it and select restore from backup...
For PC:
1) Save off the backup files as a copy somewhere
2) Connect your iPhone to the computer, but don't sync, cancel it if it starts automatically.
3) go to your iPhone in iTunes, right click on it and select restore from backup...
-- see http://www.maciverse.com/