You may not be aware that when you delete a file, the file is
not completely erased—you are merely eliminating the reference
to that file. The contents of the file will remain on your hard
drive until they’re overwritten by other data. These deleted
files can be retrieved by simple utilities or by those who know
where and how to look. In the case that you’re trying to delete
a file containing sensitive information, you should use
shredding software to prevent anyone from retrieving it. Before
selling or donating old computers, you should make sure that
sensitive data is removed. Files that are simply "dragged to the
trash" can be easily recovered, so use a secure delete utility
(such as those included with PGP and Norton Utilities) to wipe
all hard drives in the system. It is best to set for multiple
wipes, at least three passes. Here are some free shredding
software downloads that you can use to truly erase files from
your hard drive. They both work by overwriting data one or more
times before deleting the f