A computer works by executing sets of consecutive instructions called programs.As the computer is switched on, a simple program which is physically part of the machine is executed.

The boot strap program is loaded into the memory if there is no major problem with any part of the hardware.This program remains in the first sector of the hard disc if the machine can boot up from hard disc.

Parasitic virus attacks the computer and its programs when the host program is executed. As soon as the host program is executed, the parasitic virus is activated. It spreads to other computers when the affected programs are copied.

Let us find what is a computer virus and how it affects an  network. According to the University of Texas, computer virus is “a parasitic program written intentionally to enter a computer without the users permission or knowledge.” Computer viruses are often included as attachments in email messages and are often disguised as pictures, videos, or other forms of multimedia. Depending on the type of computer virus that’s been created, viruses can cause a range of damage to one’s computer system. Everything from the annoying (adding more spam to your email inbox) to the destructive (erasing all the data on your hard drive) can be caused by computer viruses.

When the term Virus was used ?

The term “virus” was actually first used by science fiction writer David Gerrold David Gerrold in his 1972 novel When Harlie Was One, as he refers to unwanted computer code in a fictional supercomputer. However, today one of the primary ways that computer viruses are spread is by an activity known as “Hacking.” 

According to Brian Harvey of the University of California, Berkeley, hackers are people “who know all about computers, and can get a computer to do anything,” and that’s precisely what hackers do to spread computer viruses around. Recently, a high-profile example of hacking occurred when the United States and Israel both claimed responsibility for hacking into the computer systems that run Iran’s nuclear enrichment facilities. The computer virus that was created and designed to be implemented via hacking was given the name Stuxnet and was America’s first use of “cyberweapons” in fighting threats overseas.

How to Know when system is infected with Virus

 Computer issues below are key to determining if your computer has been infected with a virus.It may be Parasitic virus or any other computer virus.

  • Major slow down of your computer’s performance
  • Endless pop-ups and spam
  • You’re locked out of certain settings, files, folders or your entire computer
  • Changes to your homepage
  • Unknown programs start when you turn on your computer
  • Mass emails sent from your email account
  • Your security software has been disabled
  • Your battery drains quickly
  • Frequent crashes

1 – Turn off “System Restore” – Sometimes viruses hide in system restore and can come back after being deleted.

2 – Boot it into safe mode – Always the best place to start, reboot computer and press that F8 button on start up, then start the removal process.

3 – Run System Configuration Utility – Run “msconfig” via the start menu and disable any startup programs that look suspicious, be careful. CCleaner might also help and Spybot also has a tool called RunAlyzer.

4 – Rename anti-spyware applications – If you’re having problems installing your favourite anti-spyware program because of the virus then try renaming them.

5 – McAfee Stinger – McAfee releases a free program (Stinger) for removing certain viruses.

6 – Clean the disk – Sometimes running disk cleaner can to speed up the time AV and Spyware scan times.

7 – Spyware Apps & Tools – Try MalwareBytes, SuperAntiSpyware, HijackThisSpyBotantimalware and SpywareBlaster

8 – Anti Virus Apps – Microsoft Security Essentials, AVG Free and Avira – remember not all at once!

9 – Create a bootable CD or USB Key – AVG provide a free bootable Linux distro or you can try BartPE boot disk and remove infected files and folders.

10 – Command prompt virus scanner – Download VIPRE, install and boot into safe mode (F8) and select “Networking with command prompt”. Then run scanner via the command prompt.

11 – What’s running on your computer – HijackThis generates an in depth report of registry and file settings from your computer for the real expert.

12 – Rootkits – Try these rootkits Prevx, Sophos Anti-Rootkit