How to Lock a ZIP File
Many people do not have the luxury of a personal computer at home, even in the workplace, some people share their machine with others. This can be a problem when you want the contents of a folder to remain private. ZIP files--files in which the folder contents have been compressed--are frequently used for archiving old content and can be password-encrypted using the Microsoft XP and Vista operating systems.
Right-click on the folder you want to lock. Select "Send to" and then "Compressed Folder" from the pop-up menu that appears. A new, compressed folder will be created. This is known as a ZIP file.
Right-click on the ZIP file. Select "Explore." Click on "Add a password" in the "File" menu.
Enter a password in the box provided. Re-type it in the box beneath. Press "OK." The ZIP file is now locked and accessible only by entering the password.