Norton UnErase included with Norton Utilities may be able to recover some of them if they were deleted recently and you haven't added too many new files since the deletion. I suggest also trying Tech Tool Pro. And also use Norton File Saver in the future to make recovery very easy as you can completely resore a drive even after reformatting it (if File Saver is ran on the drive first). You can have it "update" at every restart or shutdown and always have a backup that can be recovered.