What is the definition of a computer virus?

A computer virus is a program or piece of computer code that infiltrates a computer, document or another program by continuous replication through the victimized system. Viruses can be spread through emails, Internet links or in any other downloaded file.

Viruses are one of the most threatening elements to the overall health and longevity of computers. Spreaders of computer viruses employ devious tactics to trick even the most cautious users into accidentally downloading harmful files. Depending on the virus, it could take effect immediately after download, or it might lie dormant until a set of conditions is met that activates it.