Most people believe that when a file is deleted, it is permanently and irrecoverably "gone". The error in this belief is that it relies on some basic assumptions that are very far from the truth. Realistically, the following must be true in order for a file to be irrecoverably deleted: 1. The data within it must not exist anymore. 2. Any evidence that the file itself ever existed must be erased. One may ask the question "Well, if I'm deleting a file, aren't these two requirements being met?" The answer is a very grave NO. As a matter of fact, the following is true of any file that has just been deleted: 1. The data within it still exists in its entirety on your drive. 2. All evidence that the file itself existed is still very much intact. 3. Using easily accessible software tools, the file can be instantly undeleted and viewed by anyone who has access to your computer. Obviously, this poses a very significant security problem, and individual PC users who do not wish their data to be accessible after deletion are not the only ones that are subject to this predicament. Businesses, schools, government agencies, and military institutions that frequently deal with extremely sensitive, private, and confidential data are also left wide open and vulnerable to all attempts at breaching security and recovering proprietary information. This information usually represents dire consequences should it "accidentally" fall into the wrong hands. System Shield uses methods approved by the US Department of Defense (DoD 5220.22) to ensure that ALL files that have been deleted are permanently disposed of, beyond ALL possible techniques of recovery. It works by proactively finding files that have been deleted (which will still remain on your system) and eliminating the data that was once held within them, as well as permanently erasing all evidence that they ever existing on your system in the first place.