From Sam's Programs:
It will make files and folder invisible (i.e. from students or children) When you drag a file on top of FileVis it will ask you for a password (which you set up the first time you opened it). If the password is correct, the file will be hidden.When you subsequently open FileVis, it will ask you for your password, and if it is correct, it will allow you to choose which hidden files to show. You can also view a list of all your hidden files.