What is a computer virus?

A computer virus is a small
software program that
spreads from one computer to
another computer and that
interferes with computer
operation. A computer virus may corrupt or delete data on
a computer, use an e-mail
program to spread the virus
to other computers, or even
delete everything on the hard
disk. Computer viruses are most
easily spread by attachments
in e-mail messages or by
instant messaging messages.
Therefore, you must never
open an e-mail attachment unless you know who sent
the message or unless you are
expecting the e-mail
attachment. Computer viruses
can be disguised as
attachments of funny images, greeting cards, or audio and
video files. Computer viruses
also spread by using
downloads on the Internet.
Computer viruses can be
hidden in pirated software or in other files or programs that
you may download. Back to the top Symptoms of a computer
virus If you suspect or confirm that
your computer is infected
with a computer virus, obtain
the current antivirus
software. The following are
some primary indicators that a computer may be infected: The computer runs slower
than usual. The computer stops
responding, or it locks up
frequently. The computer crashes, and
then it restarts every few
minutes. The computer restarts on its
own. Additionally, the
computer does not run as
usual. Applications on the computer
do not work correctly. Disks or disk drives are
inaccessible. You cannot print items
correctly. You see unusual error
messages. You see distorted menus and
dialog boxes. There is a double extension on
an attachment that you
recently opened, such as
a .jpg, .vbs, .gif, or .exe.
extension. An antivirus program is
disabled for no reason.
Additionally, the antivirus
program cannot be restarted. An antivirus program cannot
be installed on the computer,
or the antivirus program will
not run. New icons appear on the
desktop that you did not put
there, or the icons are not
associated with any recently
installed programs. Strange sounds or music plays
from the speakers
unexpectedly. A program disappears from
the computer even though
you did not intentionally
remove the program. Note These are common signs of infection. However, these
signs may also be caused by
hardware or software
problems that have nothing
to do with a computer virus.
Unless you run the Microsoft Malicious Software Removal
Tool, and then you install
industry-standard, up-to-date
antivirus software on your
computer, you cannot be
certain whether a computer is infected with a computer
virus or not.

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