How to remove virus from my Computer?


We are interested in understanding the extent of the computer virus problem in the world today, with an eye towards being able to predict what it will be like in the future. We recommend a number of improvements, and present a different methodology for measuring various aspects of the computer virus problem which possesses some important advantages. We have studied a large, stable population of PC DOS users, recording information about virus incidents as they occurred. While the number of viruses that have been written has increased dramatically, only a small fraction has been seen in real incidents. Of this fraction, just a few viruses account for most of the incidents. While the number of incidents caused by all viruses each quarter is increasing, its increase is not nearly as dramatic as some have predicted. Some viruses are responsible for more incidents than in the past, while others are stable or declining in number. We conclude that, although there are ongoing infections by a number of viruses in the world as a whole, the susceptibility of our particular sample population to infection has decreased measurably as a result of user education, widespread dissemination of anti-virus software, and centralized reporting. Although we have learned much from our study, considerably more work is required before we can reliably forecast the most important aspects of the computer virus problem.

With the development of human civilization the technology around us is getting more and more advanced and better. And the similar case is here with computer viruses too. Along the new threats the new ideas of defenses are arising too. A computer virus is a self replicating computer program that spreads by inserting the copies of itself to other executable code or files that may be the part of some legitimate programs. The term ‘virus’ also refers to other types of malware, including adware and spyware programs but not limited to other programs that do not have the reproductive ability. Since it has the ability to multiply itself to increase its population so, perhaps it may be the reason why the most harmless viruses do simply replication and spreading to new systems. Almost all viruses are attached to an executable files which means that the viruses are not one which get spread itself to any system; it’s a human action actually which give them opportunity to perform their action. So we ourselves are responsible for the virus infection in our system unknowingly.

Origin of Computer Viruses
The origin of computer viruses was started from the “Theory of self-reproducing automata” which was published by the John von Neumann in the year 1966. The article is based on lecturers held by von Neumann at the University of Illinois about the “Theory and Organization of Complicated Automata” in 1949. Many computer programs based on the self-replicating programs were developed and experimented up to beginning of 1980s.
In the year 1981, a program called Elk Cloner written for Apple II systems were credited the first large-scale computer virus outbreak in history. It was created by Richard Skrenta. The viruses spread via floppy disk through Texas A&M.
In the year 1983, Frederick Cohen introduced the term ‘virus’ and formally defined the ‘computer virus’. Cohen demonstrated a virus-like program on a VAX11/750 system at Lehigh University. The program was able to install itself to or infect other system objects.
Later on 1986, the Brain boot sector virus was released. It was the first IBM PC compatible virus. The virus was created by two Pakistani programmers Basit Farooq Alvi (19 year old) and his brother, Amjad Farooq Alvi in Lahore, Pakistan. And it is the reason why the virus is also known as Lahore, Pakistani, and Pakistani Brain.

After a year in 1987, Jerusalem virus was detected in the city of Jerusalem. The virus is activated on every Friday the 13th, and destroys all the executable files (.exe files and .com files) and deletes any program run on that day. The virus is also popular as “Friday the 13th virus”. It was a worldwide epidemic.
Then in 1988, the first worm virus which was spread extensively “in the wild” was Morris worm. It was created by Robert Tappan Morris. It infects the DEC VAX and Sun machines running BSD UNIX machines connected to the Internet.
Now in 1989, the AIDS Trojan appeared and it was unique at that time because it demanded payment for removal.
At beginning of 1990s, the antivirus software began to appear. Then Symantec launches Norton Antivirus, one of the first antivirus programs developed by a large company.
In 1998, the first version of the CIH virus appeared.
 In 1999, the Melissa worm was released, targeting Microsoft Word and Outlook-based systems and creating considerable network traffic. It was written by David L. Smith which infected countless thousands of PCs and estimated damage of $80 million. The author was jailed for 20 months.
In 2000 year, the ILOVEYOU worm was appeared. It was created by Onel de Guzman of AMA Computer University but de Guzman himself denies being behind the outbreak. The virus damaged of 5.5 to 10 billion dollars.
In 2001, the Code Red worm was released attacking Microsoft’s Internet Information Server. It has got a lot of publicity because it also attacked the webpage of White House. It infected approx. 359,000 hosts in the first 12 hours. It was estimated the damage of $2 billion.The Sircam worm was also released spreading through e-mails and unprotected networking sharing. The Klez worm was also first identified which exploits vulnerability in Microsoft Internet Explorer and Microsoft Outlook and Outlook Express.
In 2003, the two major worms named the Sobig worm and the Blaster worm begin to attack millions of Microsoft Windows computers which cause the largest down-time and clean-up cost ever. Another SQL slammer worm became the fastest spreading worm to date. It infected 75,000 computers in approx. 10 minutes, doubling its numbers every 8.5 seconds in its first minute of infection. It is also called Sapphire worm. It attacked Microsoft SQL Server and MSDE.
In 2004, MyDoom was released and holds the record for the fastest-spreading mass mailer worm. Another Witty worm was record-breaking worm in many regards. First, it exploited holes in several Internet Security Systems products. Second, it was the fastest disclosure to worm. Third, it was the first internet worm to carry a destructive payload. And fourth, it spread rapidly using pre-populated list of ground-zero hosts.
Till now many viruses have developed and infected too many computers. It’s a very long history. We have just mentioned the most notable virus attack in the history so far. So for detail information can be viewed.

Types of Computer Viruses
There are several different types of computer viruses. And different types can have different consequences. The possible types have been expanded a lot as the operating systems have been grown more in features and complexity. So on the basis of operations that perform, the types of viruses can be divided into following types:
  • o   Boot sector viruses
  • o   File infecting viruses
  • o   Polymorphic viruses
  • o   Stealth viruses
  • o   Multi-partite viruses
  • o   Logic Bombs/Time Bombs
  • o   Macro viruses
  • o   Companion virus
  • o   Fat virus
  • o   Email virus
  • o   Overwrite virus
  • o   Resident virus
  • o   Direct Action virus

Boot Sector Virus
The virus that affects the boot sector of a floppy or hard disk is the boot sector virus. This part of disk has the information about the disk so, it is very crucial part of a disk which made possible to boot from the disk. As the system gets switched on the virus is also get activated. The best way to avoid the boot sector virus is to ensure that floppy disk are write-protected and never start your computer with an unknown floppy disk in the disk drive. Polyboot B, AntiEXE can be the examples of boot sector virus.

Polymorphic Virus
As the name suggest polymorphic, this virus encrypt or encode themselves in a different way each time they infect the system. So this makes impossible for antivirus to find them using string or signature searches. And also they make a large number of copies of themselves. Elkern, Marburg, Satan Bug and Tuareg are some of the examples of polymorphic virus.
Macro Virus
This kind of virus infects the macros of certain applications or programs. The macros of Microsoft word, excel, etc. The email virus can also have the macro virus with their attachments. Melissa A, Relax, Bablas, O97M/Y2K can be its examples.

Companion Virus
Companion virus can be considered as file infector viruses like resident or direct action types. They are known as companion viruses because once they get into the system they "accompany" the other files that already exist. In other words, in order to carry out their infection routines, companion viruses can wait in memory until a program is run (resident viruses) or act immediately by making copies of themselves (direct action viruses). Stator, Asimov.1539 and Terrax.1069 can be its examples.
Overwrite Virus
Overwrite virus usually delete the information contained in the files by rendering them partially or totally useless. The only way to clean a file infected by an overwrite virus is to delete the file completely, thus losing the original content. Way, Tri Reboot, Trivial.88.D can be its examples.

Spreading of Computer Viruses
The first task of computer viruses is to get them transmitted to another host program to get spread. Until they have a host program for transferring to, they are completely harmless. Just say they are like dead. So this can be the behavior of biological viruses. Many people compare the computer viruses to biological viruses because they have got some similarities. Like biological viruses, computer viruses show the behavior of both living and dead. They are as living when they have a host program to infect to, and as dead until they don’t found host program for infection. They are parasitic in nature as biological viruses.
Generally, the computer viruses spread in one of the three ways:
§  From removable devices
The removal devices can be pen drive very popular these days, floppy disk almost unavailable these days.
§  From the Internet downloads
The files that are downloaded from internet have the most probable chance of having viruses. So the not trusted sites should be avoided. The zip file downloaded may have the chance of virus as the antivirus doesn’t scan these files.
§  From e-mail attachments
The e-mail is also the next main reason of transferring of viruses through internet. Actually the viruses are not itself in the e-mail but it’s like a delivery person. The attachment with the e-mail contains the viruses. As the e-mail is opened the virus get trigger and is spread in the system. So, it is generally recommended not to accept the e-mail from any anonymous person.

Effects and Consequences
From the discussion above the virus can do very serious damage such as destroying everything on a person’s hard disk (like corrupting and formatting), forcing a large multinational company to waste their many hours in cleaning up the viruses. And also can have very simple damage. There are many viruses that are built for just spreading; they just get spread and do not get activated, not causing any damage. Even a silly message is also a simple virus that just displays the certain sentence of message in certain interval of time. So for these reason they legal system is getting more harshening in punishing against them.

Protection from Computer Viruses
The first thing I would like to say is “Prevention is better than cure”. Taking action after virus infection is better than to take some preceding steps earlier.
·         Assuring the firewall is turned on.
·         Updating the antivirus software after every 3 or 4 days.
·         Keeping the operating system up-to-date.
·         Scanning any removable devices before the access to it.
·         Updated antispyware software can also be used.
·         Taking the backup of the important is also wise.
But what to do if the computer is already infected? The below procedure can be applied:
·         First thing is to get relax and not to get much worry.
·         If it is sure the system is been infected then it’s better not to use your system much because the virus can cause more damage.
·         Get the information of the virus because it is important to know what kind of virus we are dealing with. Different types of virus can have different steps to eliminate it.
·         Antivirus sites can also be referred for the proceeding task.
·         Rebooting the computer with clean diskette along with antivirus in it and making a scan can also be preferred.
·         If the above steps doesn’t work format can also be preferred. And after format it is wise to scan all the system with an antivirus before accessing any of the drive in the system.
·         Sometimes the virus is of master boot record (MBR) and it get resides on it. And during the format it doesn’t get format. So when a new OS is installed again the virus gets activated and again the system gets virus infected. Finally the last step would be to have wiped the hard disk.

In the conclusion, we want to conclude that the trend of developing of computer virus is getting increased more as the development of different software and OS has came into existence. From the research, we want to predict that the trend of development of computer virus is not getting to stop and the so called defense, the antivirus is also going to have more powerful defenses against them. Since now the pace of Artificial Intelligence is getting more in action so, in the near future there would be the virus that would destroy or have small or big effect on those AI based machines. Though the computer viruses have a simple and few line coding but it has devastating effect on its target which may hinder the user in no time. So it’s wise to have better prevention before, then having cure.  


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