Whenever we delete a file, it is not actually deleted from the disk. Operating system just marks those areas of hard disk as deleted. At that time, some undelete software like Glary Undelete and Recuva can easily recover those files. A file is safely removed from the disk when it is overwritten by another file. However, even after that, it might be possible to recover data by studying the magnetic fields on the disk platter surface! This can be a problem sometimes if you were trying to delete some sensitive data, and didn’t realize that it actually stayed on disk.
Eraser is a free software that gets rid of that problem. Eraser can permanently delete files and folders from your disk so that the files can never be recovered. Eraser works by overwriting your data several times with carefully selected patterns. This completely erases all the traces of the file from hard disk, and makes it unrecoverable.
If you are disposing off your hard disk, then this software would come extremely handy. Just run this to ensure all the data on hard disk is safely deleted, so that you do not become a victim of identity theft if someone recovers the data from the hard disk.