Anything that claims to be a virus that you get just by opening your email is a hoax, because there is no way to catch a virus that way. You can set Word to warn you about macros. Real virus warnings generally include reference sources such as CIAC or well-known virus software companies like McAfee or Norton, including specific web pages you can go to for more information. Real warnings give names to contact and sources. It would also indicate what kind of computer is affected - Macintosh, Windows, Unix, VMS, etc.
Most viruses only work on one kind of computer.
Many viruses are listed there, along with details on what kind of computers and programs they infect and what damage they may do. You should visit this site. See also IBM's excellent virus and hoax site and the Mining Co.'s Urban Legend and Hoax site . If you receive a warning about an e-mail virus, do not automatically send it on. First check the above sites or contact your ISP administrator.