Example
 

Antivirus are small software programs that will spread from one computer to another and to interfere by using computer operation.
A contamination might.. corrupt or delete data on your desktop, use your e-mail process to spread itself to be able to other computers, or even erase everything on the hard disk.
Antivirus are often spread as a result of attachments in e-mail emails or instant messaging messages. That is why it is crucial that you never open e-mail attachments until you know who it’s from and you are expecting it.