Computer Virus

VIRUS stands for Vital Information Resources Under Seize 

A computer virus is a computer program (software) or a piece of code that is loaded onto your PC or Laptop without your permission. The main source of the virus is the Internet. A virus can also enter from portable storage media like Portable HDD, Pen Drive, CD, and DVD. The virus program has the property to create a number of copies and spread itself from one machine to another machine. It can affect the stored data files, boot sector of the hard drive. When the computer virus replication process successfully completed the computer is known as an infected PC. 

All software are human-made similarly viruses are also human-made programs. The main objective of these virus programs to access private/personal information, corrupt stored data, to interrupt/disturb the normal execution of computer programs. They mainly hit the host programs and spread on the execution of infected programs. 

Computer viruses cause damage to millions of computers worldwide every year. To counter viruses programmers formed anti-virus programs. 

The following effects may occur in virus-infected Computer:

Can corrupt your system file and slow down your computer system
Can make some programs corrupt or defective
Can harm a computer's hard drive boot sector
Can steal your computer's information and send it to another person
Can damage/ delete data of hard drive
Can display irrelevant and irritating messages on your computer screen

Types of Computer Viruses 

Some common types of computer viruses as follow 

Boot sector/Memory viruses

A boot sector virus is a type of virus that infects the boot sector part of the hard disk drive. This boot sector part of HDD also known as Master Boot Record (MBR).

Multipartite viruses

This type of virus is able to attack more than one part of a system like a disk boot sector, memory and stored files.

Stealth viruses

It is a very smart virus as it is able to changes the code when trying to detect it. So the detection process of viruses becomes very challenging.

Macro viruses

A macro virus can be found in spreadsheet files. These are codded in high-level languages. These viruses are triggered automatically when a program executes.

Polymorphic viruses

This type of "shape-shifting" virus produces malicious code that reproduces itself infinitely and constantly changes its characteristics. This can beat your computer defenses/security and eventually harm your system.

Active X viruses

ActiveX is a virus built into your web browser.

Browser hijacker 

A browser hijacker is a malware program that modifies web browser settings without the user's permission.