Answer:
Computer viruses usually spread in one of three ways: from removable media; from downloads off the Internet; and from e-mail attachments. Although the Internet gets a bad rap as a source of viruses, you're no more likely to contract a virus from the Web than you are from packaged software.
1)when the software or documents they get attached to are transferred from one computer to another using a network,2) a disk, 3)file sharing methods, 4)or through infected e-mail attachments.
