This article is from the Computer Virus for New Users FAQ, by Nick email@example.com with numerous contributions by others.
You can't get a virus just by reading a plain-text E-mail message or Usenet
post. What you have to watch out for are encoded messages containing
that include an executable file attachment (i.e., an encoded program file or
a Word document containing macros).
In order to activate a virus or Trojan horse program, your computer has to
execute some type of code. This could be a program attached to an E-mail, a
Word document you downloaded from the Internet, or something received on a
floppy disk. There's no special hazard in files attached to Usenet posts or
E-mail messages: they're no more dangerous than any other file.