Permanent PC file removal must be done by a data eraser
Simply deleting a file on your computer does not remove the information contained in that file from your computer’s hard drive. All that file deletion accomplishes is to mark the area used by that file as available for rewrite. If you have sensitive or private information on your computer that must be disposed of with absolute certainty, it must be erased by use of a data eraser. This kind of information removal program will break down the information stored on areas of a hard disk allocated to files or folders and endlessly scramble the information contained in such a way as it can never be reconstructed.
Related:
Deleted file recovery software
Recover files just delete Windows XP
SD card video recovery
Is it possible to restore data after formatting a HD
Digital photos and videos recovery
Linux data recovery software
Hard disk recovery freeware
File Eraser Utility
Ext2 File recovery
How to Recover deleted files