File Infector virus' infect uninfected programs when they are executed in memory. In other cases they are infected when they are opened, occasionally the virus simply infects all of the files in the directory it was run from. The file-infector class is also used to refer to programs that do not physically attach to files but associate themselves with program filesnames. A Boot Sector virus is loaded into memory upon boot-up, before virus detection code can be executed. As computers have grown more powerful, the tasks have become more complex.
Some macro languages offer the ability to write files other than the original document.
Very informative site for beginners. A very good independent antivirus information source. Norton AntiVirus A site with all the Norton AntiVirus tools and support. The truth about email viruses Go to this site to read up on the latest and most popular way of infection. You cannot contract a virus by just reading an email, but your computer CAN be infected if you download and execute the attachment that comes with the email.