As you know, once you have deleted a file or folder, it still could be recovered very easily even if you have emptied the Recycle Bin. To prevent the recovery of deleted files, you should physically replace the contents of deleted files by any data. Of course, this is done by using special programs, not manually.
There are two types of the programs that can wipe previously deleted files without any chance for them to be recovered (even using special recovery tools). The first type of such programs will overwrite the entire free disk space on your hard disk (we call it a 'blind mode'). They usually work for 3-10 hours, carefully destroying all possible remainders of deleted files' data. The second type of those programs will securely erase only selected files within a much shorter time--usually a few minutes--providing the same level of security. Our program belongs to the second type, and we are confident that it's the best type.