From Alfa Programs:
Alfa Folder Locker is a small free software to lock any folder with password. The folder will be secured by the password against open, copy, move, and delete. The locking process is so fast " less that 1 sec " and all data will be secured even if you check the show hidden files on your system. You can protect any number of folders by different passwords. The program has integrated context menu, so you can easily lock or unlock any folder by right click it. The program is easy to use and has a friendly user interface.