A lot of times when something is deleted in reality it doesn't go away completely, it is just not accessible to you anymore and not visible. However even in the most severe cases there is a possibility that the erased files can be reconstructed.
Disk Drill is a partition recovery software that offers effective recovery methods on different levels for any data loss situation. To help Disk Drill recover a deleted partition try to stop using the hard drive, connect it into an external docking station, and ideally, boot from a different computer or system drive.
Disk Drill offers free scan for partition recovery to see what files can be restored. And don't forget that Basic edition for Windows
lets you undelete up to 500 MB for free.