"Anti Autorun-7" make "vaccination" to a removable disk: create folder "autorun.inf" and "special" file which do not require space. You can set or remove protection and see information about removable disks. So virus on infected computer can not write "autorun.inf" file and infect any other computer when you plug in a removable disk. Periodically inspect your removable disks and delete unknown files and folders. Please note: "Anti Autorun-7" may not help you if removable disk already is infected and can not help if your computer is infected. This is prevent utility.