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