I know this is not the answer you want to hear, but what I would recommend doing is creating a new account and copying all your data across. The ntuser.dat file holds the entire "Hkey_Current_User" hive for that user. Your documents will not be damaged, but recovery of that file will be difficult. If you have any problems with restoring your data, such as Outlook files, then just reply back.
If you do want to attempt recovery, see if you can undelete the file using Recuva then copy it back: Recuva - Download
If you have any Shadow hard disk copies or backups of this file, then import them now. Else try System Restore, it may just do the trick. If you have to resort to Recuva, then your chances of succes are almost nil.