I second ryansoh3
's suggestion to use Recuva
(although his suggestion to clone should be unnecessary because this isn't a failing HDD).
If the data hasn't been overwritten (the files were just deleted/emptied from recycle bin, or the drive was quick formatted), Recuva should be able to recover just about everything.
However, if the files were shredded/wiped, they are gone forever.
When you start Recuva, bypass the wizard. Click [Options], go to the "Actions" tab, and enable "Deep Scan", "Scan for non-deleted files" and "Restore folder structure." Then click [OK], select the desired disk in the dropdown on the upper-left and click "Scan." When it is done scanning, select the files that you want to recover (you can select all of them), and then recover them to a different disk (important)