WipeFree

When you delete a file, data is not immediately removed from your system. Instead, the operating system marks positions on the disk as "free" -- until new data comes along, the old data still exists.

WipeFree command line application solves this problem by creating a file which takes up the remaining available disk space. This file's data (which is random garbage) replaces any other data which may have still been lying around. This temporary file is automatically deleted, and the result is that the disk no longer contains any previously deleted information. Note, however, that the file names of deleted files may still exist.

WipeFree can be used on hard disks, floppy diskettes, and removable drives. It will work on any file system -- FAT16, FAT32, NTFS, HPFS. The generated temporary file contains random data (it can not be compressed), and the file cache is flushed, so the procedure is quite secure.