The virus program will load first, before even the operating system. Trojan horse . Some virus experts do not classify Trojan horse programs as true viruses, because they generally do not copy themselves. There are many scares which get passed around the Internet about viruses transmitted by e-mail. They are only scares, though.
Viruses have to be executed, just like other computer programs.
You cannot get a computer virus just by reading text e-mail . If someone you do not know or trust sends you a program or file as an attachment, that might contain a virus, but it cannot infect your computer unless you make the effort to save the attachment and then run the program. Anti-Virus Programs Viruses are only programs, and can be eliminated from a computer just as any program can be erased. There are many anti-virus tools available which allow users to find any viruses that might be on their computer and eliminate them before they do any damage, or even before any of the early clues mentioned above show up. No computer which is going to receive programs from other computers should be without some anti-virus tool.