What are computer viruses?

Question

I know they're bad. But I don't understand where they come from, how they are created, how they are able to infect your computer, and what files are most likely to get corrupted. Anyone with info, I'd really appreciate it.

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.

Many viruses have extra features, which allow them to escape detection by antivirus software. Such threats use several approaches to stay hidden. Some of them, known as stealth viruses, monitor antivirus software activity and intercept its requests to the operating system. When the antivirus attempts to check an infected file, the virus immediately passes the original clean variant of that file, so the antivirus is unable to find any malicious code in it. Other parasites, called polymorphic viruses, are able to mutate continuously modifying their code, so that two files infected by the same pest have no common parts. Polymorphic viruses are extremely difficult to detect.

hope this helps

Answer 2

YES YES YES A Computer Virus Nothing But Codes Generated Using Any Programming Languages. It Can Be Either Malicious Code Or Executable File. In Case of Codes They Are Attached With Another Data File(s). Executable Files Infect The System When Executed With Or Without User Attention. As Said Before Viruses Are Nothing But Computer Programs/Codes. THEY CAN DO ANYTHING TO HARM YOUR COMPUTER. Hope It Helps... Thank for Reading Till End... :) (y)

Answer 3

2

Answer 4

Well a file is just a string of data with a special marker at the end called EOF "End of File". Some viruses add information to a file and move the EOF marker. Other viruses are files themselves that run as a service.

A virus really is just another computer program. However, because fo the nature of the computer program it is termed a virus. Viruses by nature are malicious.

Any file can be corrupted by a virus, but coders seek out the most commonly used files such as Operating System files and files related to Microsoft Office.

Some viruses allow a hacker to gain entry to a system to retrieve data or host files.

Answer 5

Viruses - A virus is a small piece of software that piggybacks on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.

for everything about viruses and to find how it works, go here;
http://computer.howstuffworks.com/virus.htm

Answer 6

Viruses and spywares are programs launched in the net by people to meet their self-interests. Spy wares reside in your PC and spies your actions. Virus is meant for affecting the normal performance of the PC. I can give a few links that offer free virus and spy ware removers. Please visit the following site and select a suitable free antivirus.
http://tinyurl.com/ymctqq
You can visit the following site , if you want a more effective antivirus . You have to pay for it!
http://tinyurl.com/ykzjyp
You also try to select and install a suitable spy ware from the following link to protect the Pc against spyware attacks.
http://tinyurl.com/ygvyzh

Answer 7

Hey,
A good tool I used to clean up and speed up my PC is CCleaner. You can download it for free here http://bitly.com/UrANQa
It's a very good program and easy to use.