When you say that no changes have been made to your system since the files were deleted, do you mean that the computer has been powered off for 6 months? If that's the case, remove the hard drive, connect it to another PC using an external drive connector, and run some file recovery software against the drive.
However, your odds of recovery are slim to nil if you've been using it all along. Even if you haven't installed any programs or made any deliberate changes, other activities in the background have surely been writing to the disk (internet cache, disk defragging, paging, etc.). In that case, your files are hosed.
Using Windows Backup/Restore is useless if you never made an original backup. If Recuva didn't find anything, then it didn't find anything.
If the hard drive hasn't been formatted in between the time the files were deleted and now, you can try to right-click the folder which contained the files and check the "Previous Versions" tab. If you're lucky, they might be shadow-copied.