Recently, I got infected with the Ravmon worm, so I got rid of it, but this is only a warning. The ravmon worm ussualy hides itself to the removbale medias (like USB flash disks, Mass storage MP3 players...) in ther boot sectors, or in their root-kits (if any). So that only a small population of firewalls can detect it. I got rid of it with my always updated anti virus program, but i bought it, so i don't know how it will work with those free anti-vir's, so be careful, and don't download suspicious files directly to your removbale media. (My care for you is that before posting a download link here, I always download it by myself and run a virus and spyware scan on it)