If you're really concerned about getting these files back, don't write to that partition AT ALL until you get them back. Meaning do not create or modify any files, run any programs, or boot into an operating system from the partition those files were orginally on. And for the love of God, do not run defrag.
Boot onto a
different partition from where the missing files were, install a data recovery program on a different partition, and attempt to restore the files onto a different partition.
I can recommend a $50 program called
R-Studio. I was able to recover about 100GB worth of lost data with it after a partition just disappeared one day.