Probably because they are. The vast majority of nasties are in the .exe files. Since this is my first day I won't stick my neck out with a cureall suggestion. However, I can agree with the amount of virus/malware/spyware alerts I get from Panda, ewido and zone alarm. The bulk of them related to worm.VB.an. It's irritating to say the least but that's what you get when you share. Many of the shared files are not used so the owners are not aware they are infected and the HD on is oblivious to them.