what is computer virus?how it works?

Answer 1

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http://uk.groups.yahoo.com/group/arc_pc_clinic/

http://uk.groups.yahoo.com/group/arc_pc_clinic/

i do not like putting big long answers like below i have most of them in the group and if you need an answer just email the group for the answer to your question if it is not in the data base

Computer viruses, worms and Trojans
What they are and what they can do
Computer viruses are self-executing, replicating programs written
specifically to change the way a machine works, without the knowledge
(or permission) of the operator/owner. Viruses are so called because
they behave in a similar way to biological viruses. Just as biological
viruses pass from person to person, replicating themselves as they go,
computer viruses pass from computer to computer. Unlike most
biological viruses, however - computer viruses are entirely man made.
Viruses can seriously damage your machine
Viruses can impair and seriously damage your computer (or network
server) by, amongst other things; executing random text, audio and
video messages, draining memory, deleting files, corrupting programs -
even reformatting (erasing the contents of) your hard disk. At best,
the less destructive variants are irritating and will slow the
infected machine up (because of the drain on memory), often resulting
in crashes and other unpredictable behaviour which can ultimately
result in loss of data.
Although a virus needs an infected application to be launched in order
to infect other programs or documents, they can conceal themselves in
your computer (often masquerading as innocent files) and replicate
(make copies of) themselves until such an infected application is
launched.
Not all viruses behave in precisely the same way and not all malicious
programs are viruses (like Trojans). Some viruses are only active
whilst an infected application is running, whilst others will stay
active in memory until you turn off your computer. However, as the
virus is resident in a file or on a disk, exiting the infected
application or turning off your computer only removes the virus from
memory, it does not remove the virus from the infected file or disk
and the virus just lays dormant, until you to reboot your computer
and/or access the infected application.
The various forms of computer viruses
Boot sector viruses infect the boot sector of a hard drive or floppy
disk by first overwriting/moving the original boot code and then
moving the original code to another sector on the disk, which the
virus marks as bad.
File infecting viruses attach/modify any executable files, sometimes
replacing the original code with its own.
Macro viruses are self replicating macros that self replicate and can
spread rapidly on a computer and/or network.
Master Boot Record Infectors infect a system's Master Boot Record on
hard drives and the Boot Sector on floppy diskettes.
Multi-partite viruses are commonly a combination of techniques of both
boot sector viruses and file infecting viruses.
Polymorphic viruses are difficult to detect as they use an encryption
algorithm that changes, along with the viruses' appearance, change
their appearance with/after each infection.
Stealth viruses hide themselves from a computers' operating system and
anti-virus products.
Viruses (including worms) are often distributed via attachments in
e-mail spam and, ironically, a great deal of e-mail spam (particularly
chain letters) are virus hoaxes.
Computer viruses, worms and Trojans
What they are and what they can do
Worms are computer programs that can copy themselves from machine to
machine, extremely quickly, through computer networks.
Computer worms differ from computer viruses because they run
independently and do not need a host file, boot sector or file
transfer between machines to propagate.
Worms
There are different types of computer worms that spread through
various services - including e-mail and instant messaging clients.
E-mail worms
these are spread via infected e-mail messages in the form of an
attachment or link to an infected Web site - some e-mail worms will
also spoof e-mail addresses.
IM worms
These are spread via instant messaging clients, to entire contact
lists, in the form of links to infected Web sites.
Internet worms
These are spread when the Internet worm scans, tries to connect and,
if successful gains access to any vulnerable machines - either by
scanning the Internet and/or using the local operating system.
IRC worms
These are spread via IRC channels in the form of infected files or
links to infected Web sites.
File-sharing Networks Worms
these are spread from shared folders via the P2P network.
Computer viruses, worms and Trojans
What they are and what they can do
Worms are computer programs that can copy themselves from machine to
machine, extremely quickly, through computer networks.
Computer worms differ from computer viruses because they run
independently and do not need a host file, boot sector or file
transfer between machines to propagate.
Worms
There are different types of computer worms that spread through
various services - including e-mail and instant messaging clients.
E-mail worms
these are spread via infected e-mail messages in the form of an
attachment or link to an infected Web site - some e-mail worms will
also spoof e-mail addresses.
IM worms
These are spread via instant messaging clients, to entire contact
lists, in the form of links to infected Web sites.
Internet worms
These are spread when the Internet worm scans, tries to connect and,
if successful gains access to any vulnerable machines - either by
scanning the Internet and/or using the local operating system.
IRC worms
These are spread via IRC channels in the form of infected files or
links to infected Web sites.
File-sharing Networks Worms
these are spread from shared folders via the P2P network.

Answer 2

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Answer 3

Also computer virus is a program also like a worm your computer ip to that the person you crashing cmputer sends a middle tect and that sends info like a bomb it just blows up windows or w/e you are useing

Throjan are people can control computer like if you put in computer ip then you could control it " hint " hint " ( If i had a throjan would be bad i have 4 people in my house that haves the same computer ip )

Keyloggers are for sending in a file gos the computer ip and copys from the keyboard code is ' AAxs 99889 ƒ 88ss keyboard ' ( then would say here keyboard type )

Also if you think im a geek im not i dont wear glasses i skateboard and stuff i just know this info because i used to make this programs for bestbuy

Answer 4

Basically, a computer virus is a software program that replicates itself and attempts to spread from file to file, system to system either with or withour intent. A lot of them cause damage to files and boot sectors and will ruin your operating system software.

If you need a more detailed response, go to:

http://en.wikipedia.org/wiki/Computer_virus

Answer 5

I am the Amanda at my work :) I'm the one that does the bulk of answering phones. My co-worker will pitch it when more than 1 line is ringing or if I'm not here.

Answer 6

Hi, if you want a lot of information about computer viruses, I'd start at the Wikipedia entry: