What is a virus?

Question

what is a virus? which one is the free software to remove virus
from system?

Answer 1

A virus is a malicious computer program or programming code that replicates by infecting files, installed software or removable media. A virus usually carries a destructive payload, which varies depending on the virus author’s intentions. A typical virus infects, corrupts or deletes files and folders, damages the system, drops other dangerous parasites, steals or discloses user sensitive information. Extremely dangerous viruses can also wipe out all the data from hard disks and even severely damage certain computer hardware devices.

By replication approaches viruses are divided into three main categories:
1. parasites called file infectors are designed to propagate by infecting or corrupting various files;
2. threats known as boot record infectors spread through removable media containing infected executable code and insert themselves into the master boot record (MBR) on hard disks;
3. widely spread macro viruses affect certain applications such as Microsoft Word or Microsoft Excel and infect documents that can contain macros.

Some viruses do not belong to any of these categories, as they combine features and functions specific to more than one virus type. Such threats, sometimes called hybrid viruses, can infect both files and master boot record and replicate by attaching malicious code to user documents. These parasites are very difficult to completely get rid of, as they usually consist of several components, which automatically reinstall each other after the user have found and removed few of them.

Answer 2

A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

The term comes from the term virus in biology. A computer virus reproduces by making, possibly modified, copies of itself in the computer's memory, storage, or over a network. This is similar to the way a biological virus works.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.

softwares..i dont know what u mean

Answer 3

You can download free antivirus programme from :
http://free.grisoft.com/freeweb.php/doc/5390/lng/us/tpl/v5

Virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

Answer 4

A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

The term comes from the term virus in biology. A computer virus reproduces by making, possibly modified, copies of itself in the computer's memory, storage, or over a network. This is similar to the way a biological virus works.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.

Answer 5

Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation.

A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk.

Viruses are most easily spread by attachments in e-mail messages or instant messaging messages. That is why it is essential that you never open e-mail attachments unless you know who it's from and you are expecting it.

Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files.

Viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programs you might download.

To help avoid viruses, it's essential that you keep your computer current with the latest updates and antivirus tools, stay informed about recent threats, and that you follow a few basic rules when you surf the Internet, download files, and open attachments.

Once a virus is on your computer, its type or the method it used to get there is not as important as removing it and preventing further infection.


I have no idea which software is the free one to remove a virus from your system, but I am pretty sure there are a few out there. Just type "free software to remove virus."

Answer 6

A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

The term comes from the term virus in biology. A computer virus reproduces by making, possibly modified, copies of itself in the computer's memory, storage, or over a network. This is similar to the way a biological virus works.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.

Good free antivirus is Avast. Join my forum- http://www.theitkgroup.net/ and get many good tips and tricks.

Answer 7

There are different types of computer viruses. Worms are viruses that makes copies of itself until your hard drive is filled up with useless files. When this happens, your pc will freeze up & become useless. A Trojan virus hides itself inside a "useful" program but in reality opens a back door for hackers to have access in your system. Bombs are viruses that activate itself at a pre-determined date.

In short, viruses are codes/computer programs that are installed in your system without your knowledge.

Computer virus are only active when your pc is powered on. It can be transfered from one pc to another by sharing of infected files.

Try Norton & Mcafee. They offer 30 days trial period.

Answer 8

Since you can't get on the internet, do you have a second computer (at work for instance) at your disposal? If you also have a flash drive or MP3 player, you could download a free anti-virus program like Avast or AVG onto this drive and then install it into your infected computer and go from there.

Answer 9

To make an analogy, the most deadly virus worldwide is malaria---spread by the mosquito. Computers are now worldwide---look at us. It is inevitable that the use of your computer will be subject to getting "infected". The flu developes different strains---and so will the aids virus. We are ALL in danger. Sorry, I know you were specifically asking about computers, but think about it. The first thing that I mentioned is in The Guinness Book Of Records.

Answer 10

I purchased StopSign. If you are unable to erase all of the virus they will help you, even go as far as writing a program just for you.

You can also do a full scan from their website.