How to remove computer virus?

Malicious codes by design are intended to make their detection and removal from the infected machine tedious, annoying, aggressive, and very difficult not only for the average user but for computer experts as well. Manual detection of viruses is virtually impossible. This highlights the need not only for a competent but updated protection program but also to provide real time security with the capability of automatically updating its virus database engine. Because malicious codes differ from one another not only in payload but also in the manner of execution, the same can be said about anti-virus programs in their ability to detect and remove perceived threats from compromised machines. Majority of computer viruses in the market target the Microsoft Windows Operating System platform not only because it is the most widely used but also it is perceived to contain a lot of security loopholes and vulnerabilities which can also be found in the Internet Explorer Web browser.

Materials Needed:

- Web browser
- Internet connection
- recovery disc
- Windows CD installer
- anti-virus program
- malware scanner software

Step 1

To remove an infection caused by a virus code, it is necessary to first reboot the machine into safe mode. This may be done by clicking on the 'Start' button, choosing 'Turn Off Computer', and selecting the 'Restart' option.

Step 2

During the reboot process, after the 'Power On Self Test' procedure, press the 'F8' key until the boot option window comes up. Select the 'Safe Mode with Networking' option and press the 'Enter' key.

Step 3

When the Operating System loads, go to the Sysinternals website to download and install the Autoruns tool to the root directory of the local storage.

Step 4

Upon completion of the installation process, launch the Autorun application by clicking on the autoruns.exe file.

Step 5

Click on the program’s Options Menu and make sure to click on the Include Empty Locations, Hide Signed Microsoft Entries, and Verify Code Signature options to enable them.

Step 6

Press the F5 key on the keyboard in order to refresh the status of the startup list and implement these new settings.

Step 7

Look under the Services or the Logon tabs for suspicious file names and processes. Check also the other tabs in case there are multiple occurrences of the malicious files. Click on the questionable files. Consult the Startup Database website in case of doubt. In most instances, these malicious files attempt to mimic legitimate Windows processes.

Step 8

Right click on the chosen malicious files and select the Delete option. They will be removed from the startup entry of the Windows Registry.

Step 9

Click on the 'Start' button and choose the 'My Computer' option. Navigate to the folder identified to be used by the virus and right click on it. Choose the 'Delete' option and click on the 'OK' button.

Step 10

Right click on the 'Recycle Bin' and choose the option 'Empty Recycle Bin' to permanently remove the malicious files.

Step 11

Click on the 'Start' button, select 'Turn Off Computer' and choose the 'Restart' option. Allow the machine to boot into normal mode by just waiting for the desktop to load.

Step 12

Part of the removal process is to make sure that future infections can be prevented. Open the Web browser and go to the Microsoft website.

Step 13

From the Microsoft Download Center, download and install the Windows Defender (bundled with Windows Vista but not with Windows XP) as well as the Malicious Software Removal Tool. The Malicious Software Removal Tool is not designed to prevent virus infection but to remove existing ones. Also, download any available updates for the Operating System and the Internet Explorer browser.

Step 14

After completing the download and installation process, run these tools to make sure that there are no more remnants of the virus.

Why Virus is Created?

There are several reasons for creating virus in the today's world.Unlike biological viruses, computer viruses do not simply evolve by themselves. They cannot come into existence spontaneously, nor can they be created by bugs in regular programs. They are deliberately created by programmers, or by people who use virus creation software.

Virus writers can have various reasons for creating and spreading malware. Viruses have been written as research projects, pranks,vandalism, to attack the products of specific companies, and to distribute political messages. Some people think that the majority of viruses are created with malicious intent. On the other hand, some virus writers consider their creations to be works of art, and see virus writing as a creative hobby. Additionally, many virus writers oppose deliberately destructive payload routines. Some viruses were intended as "good viruses". They spread improvements to the programs they infect, or delete other viruses. These viruses are, however, quite rare, still consume system resources, and may accidentally damage systems they infect. Moreover, they normally operate without asking for permission of the owner of the computer. Since self-replicating code causes many complications, it is questionable if a well-intentioned virus can ever solve a problem in a way which is superior to a regular program that does not replicate itself. In order to replicate itself, a virus must be permitted to execute code and write to memory. For this reason, many viruses attach themselves to executable files that may be part of legitimate programs. If a user tries to start an infected program, the virus' code may be executed first. Viruses can be divided into two types, on the basis of their behavior when they get executed. Nonresident viruses immediately search for other hosts that can be infected, infect these targets, and finally transfer control to the application program they infected. Resident viruses do not search for hosts when they are started. Instead, a resident virus loads itself into memory on execution and transfers control to the host program. The virus stays active in the background and infects new hosts when those files are accessed by other programs or the operating system itself.

Computer Virus

The word VIRUS is different from the "medical virus". It is the abbrivation of "Victor Information Resources Under Seage".

The term "virus" was first used in an academic publication by Fred Cohen in his 1984 paper Experiments with Computer Viruses, where he credits Len Adleman with coining it. However, a mid-1970s science fiction novel by David Gerrold, When H.A.R.L.I.E. was One,includes a description of a fictional computer program called "VIRUS" that worked just like a virus (and was countered by a program called "ANTIBODY"); and John Brunner's 1975 novel The Shockwave Rider describes programs known as "tapeworms" which spread through a network for deleting data. The term "computer virus" with current usage also appears in the comic book "Uncanny X-Men" No. 158, published in 1982. And even earlier, in 1973, the phrase "computer virus" was used in the movie Westworld to describe a malicious program that emerged in the computer system of the theme park. Therefore, we may conclude that although Cohen's use of "virus" may, perhaps, have been the first "academic" use, the term has been used earlier.The term "virus" is often used in common parlance to describe all kinds of malware (malicious software), including those that are more properly classified as worms or trojans. Most popular anti-viral software packages defend against all of these types of attack.Viruses cause much damage to computers, today worse than before. A good way to stop viruses,is to keep a healthy firewall,and not let anyone put their own floppy disks, or cd's in your home computer.

Online Hacking

What Is Online Hacking?

It basically happens when a hacker exploits a security breach in a network or computer and is able to access the information through the internet. As long as he is not detected or the computer shut down, he will be able to hack the computer as long as it is online. It doesn’t matter if you have a broadband connection or a dial up, internet hackers

can access your home computer security if you haven’t taken adequate measures for protecting yourself. It is like leaving a car parked in the street. If you leave it with the windows open, the keys inside and the radio mask still placed in the console, it’s quite probable you will suffer a robbery. Unfortunately, with computers it is a little more difficult since you don’t see those opened windows. The only way to find them is looking for them with specialized software.

Parts of a computer

If you use a desktop computer, you might already know that there isn't any single part called the "computer." A computer is really a system of many parts working together. The physical parts, which you can see and touch, are collectively called hardware. (Software, on the other hand, refers to the instructions, or programs, that tell the hardware what to do.)

The illustration below shows the most common hardware in a desktop computer system. Your system may look a little different, but it probably has most of these parts. A laptop computer has similar parts but combines them into a single notebook-sized package.

About Bluetooth

What Is Bluetooth?

 Bluetooth is the name of a new technology that is now becoming commercially available. It promises to change         significantly the way we use machines.The art of connecting things is becoming more and more complex every day. In this article, we will look at a method of connecting devices, called Bluetooth, that can streamline the process. A Bluetooth connection is wireless and automatic, and it has a number of interesting features that can simplify our daily lives.

Why is it called Bluetooth?

Harald Bluetooth was king of Denmark in the late 900s. He managed to unite Denmark and part of Norway into a single kingdom then introduced Christianity into Denmark. He left a large monument, the Jelling rune stone, in memory of his parents. He was killed in 986 during a battle with his son, Svend Forkbeard. Choosing this name for the standard indicates how important companies from the Nordic region (nations including Denmark, Sweden, Norway and Finland) are to the communications industry, even if it says little about the way the technology works.

How Bluetooth Creates a Connection

Bluetooth takes small-area networking to the next level by removing the need for user intervention and keeping transmission power extremely low to save battery power. Picture this: You're on your Bluetooth-enabled cell phone, standing outside the door to your house. You tell the person on the other end of the line to call you back in five minutes so you can get in the house and put your stuff away. As soon as you walk in the house, the map you received on your cell phone from your car's Bluetooth-enabled GPS system is automatically sent to your Bluetooth-enabled computer, because your cell phone picked up a Bluetooth signal from your PC and automatically sent the data you designated for transfer. Five minutes later, when your friend calls you back, your Bluetooth-enabled home phone rings instead of your cell phone. The person called the same number, but your home phone picked up the Bluetooth signal from your cell phone and automatically re-routed the call because it realized you were home. And each transmission signal to and from your cell phone consumes just 1 milliwatt of power, so your cell phone charge is virtually unaffected by all of this activity.

The Problem
When any two devices need to talk to each other, they have to agree on a number of points before the conversation can begin. The first point of agreement is physical: Will they talk over wires, or through some form of wireless signals? If they use wires, how many are required -- one, two, eight, 25? Once the physical attributes are decided, several more questions arise:

• How much data will be sent at a time? For instance, serial ports send data 1 bit at a time, whil e parallel ports send several bits at once.
• How will they speak to each other? All of the parties in an electronic discussion need to know what the bits mean and whether the message they receive is the same message that was sent. This means developing a set of commands and responses known as a protocol.

Bluetooth offers a solution to the problem.

WIFI Networks

If you've been in an airport, coffee shop, library or hotel recently, chances are you've been right in the middle of a wireless network. Many people also use wireless networking, also called WiFi or 802.11 networking, to connect their computers at home, and some cities are trying to use the technology to provide free or low-cost Internet access to residents. In the near future, wireless networking may become so widespread that you can access the Internet just about anywhere at any time, without using wires.


What is WiFi?

A wireless network uses radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication. Here's what happens:

1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
2. A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.

The process also works in reverse, with the router receiving information from the Internet, translating it into a radio signal and sending it to the computer's wireless adapter.

The radios used for WiFi communication are very similar to the radios used for walkie-talkies, cell phones and other devices. They can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and convert the radio waves back into 1s and 0s. But WiFi radios have a few notable differences from other radios.

• They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is considerably higher than the frequencies used for cell phones, walkie-talkies and televisions. The higher frequency allows the signal to carry more data.
• They use 802.11 networking standards, which come in several flavors:
  • 802.11a transmits at 5 GHz and can move up to 54 megabits of data per second. It also uses orthogonal frequency-division multiplexing(OFDM), a more efficient coding technique that splits that radio signal into several sub-signals before they reach a receiver. This greatly reduces interference.
  • 802.11b is the slowest and least expensive standard. For a while, its cost made it popular, but now it's becoming less common as faster standards become less expensive. 802.11b transmits in the 2.4 GHz frequency band of the radio spectrum. It can handle up to 11 megabits of data per second, and it uses complementary code keying (CCK) modulation to improve speeds.
  • 802.11g transmits at 2.4 GHz like 802.11b, but it's a lot faster -- it can handle up to 54 megabits of data per second. 802.11g is faster because it uses the same OFDM coding as 802.11a.
  • 802.11n is the newest standard that is widely available. This standard significantly improves speed and range. For instance, although 802.11g theoretically moves 54 megabits of data per second, it only achieves real-world speeds of about 24 megabits of data per second because of network congestion. 802.11n, however, reportedly can achieve speeds as high as 140 megabits per second. The standard is currently in draft form -- the Institute of Electrical and Electronics Engineers (IEEE) plans to formally ratify 802.11n by the end of 2009.
• Other 802.11 standards focus on specific applications of wireless networks, like wide area networks (WANs) inside vehicles or technology that lets you move from one wireless network to another seamlessly.
• WiFi radios can transmit on any of three frequency bands. Or, they can "frequency hop" rapidly between the different bands. Frequency hopping helps reduce interference and lets multiple devices use the same wireless connection simultaneously.

As long as they all have wireless adapters, several devices can use one router to connect to the Internet. This connection is convenient, virtually invisible and fairly reliable; however, if the router fails or if too many people try to use high-bandwidth applications at the same time, users can experience interference or lose their connections.

Wireless Networks

"Wireless technology is a truly revolutionary paradigm shift, enabling multimedia communications between people and devices from any location. It also underpins exciting applications such as sensor networks, smart homes, telemedicine, and automated highways. This book provides a comprehensive introduction to the underlying theory, design techniques and analytical tools of wireless communications, focusing primarily on the core principles of wireless system design. The book begins with an overview of wireless systems and standards. The characteristics of the wireless channel are then described, including their fundamental capacity limits. Various modulation, coding, and signal processing schemes are then discussed in detail, including state-of-the-art adaptive modulation, multicarrier, spread spectrum, and multiple antenna techniques. The concluding chapters deal with multiuser communications, cellular system design, and ad-hoc network design. Design insights and tradeoffs are emphasized throughout the book. It contains many worked examples, over 200 figures, almost 300 homework exercises, over 700 references, and is an ideal textbook for students. The book is also a valuable reference for engineers in the wireless industry."
Wireless network
Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes are implemented without the use of wires.^[1] Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network

Wireless PAN

Wireless Personal Area Networks (WPANs) interconnect devices within a relatively small area, generally within reach of a person. For example, Bluetooth provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports WPAN applications. Wi-Fi PANs are also getting popular as vendors have started integrating Wi-Fi in variety of consumer electronic devices. Intel My WiFi and Windows 7 virtual Wi-Fi capabilities have made Wi-Fi PANs simpler and easier to set up and configure

Wireless LAN

A wireless local area network (WLAN) links two or more devices using a wireless distribution method (typically spread-spectrum or OFDM radio), and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network.

• Wi-Fi: Wi-Fi is increasingly used as a synonym for 802.11 WLANs, although it is technically a certification of interoperability between 802.11 devices.
• Fixed Wireless Data: This implements point to point links between computers or networks at two locations, often using dedicated microwave or laser beams over line of sight paths. It is often used in cities to connect networks in two or more buildings without physically wiring the buildings together.

Wireless MAN

Wireless Metropolitan area networks are a type of wireless network that connects several Wireless LANs.

• WiMAX is the term used to refer to wireless MANs and is covered in IEEE 802.16d/802.16e.

Wireless WAN

wireless wide area networks are wireless networks that typically cover large outdoor areas. These networks can be used to connect branch offices of business or as a public internet access system. They are usually deployed on the 2.4 GHz band. A typical system contains base station gateways, access points and wireless bridging relays. Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photo-voltaic solar panels or wind systems they can be stand alone systems.it

Pascaline

Pascaline

In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one-function calculator (it could only add) but couldn't sell many because of their exorbitant cost and because they really weren't that accurate (at that time it was not possible to fabricate gears with the required precision). Up until the present age when car dashboards went digital, the odometer portion of a car's speedometer used the very same mechanism as the Pascaline to increment the next wheel after each full revolution of the prior wheel. Pascal was a child prodigy. At the age of 12, he was discovered doing his version of Euclid's thirty-second proposition on the kitchen floor. Pascal went on to invent probability theory, the hydraulic press, and the syringe. Shown below is an 8 digit version of the Pascaline, and two views of a 6 digit version:

History of computers

The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task.

ABACUS
The abacus was an early aid for mathematical computations. Its only value is that it aids the memory of the human performing the calculation. A skilled abacus operator can work on addition and subtraction problems at the speed of a person equipped with a hand calculator (multiplication and division are slower). The abacus is often wrongly attributed to China. In fact, the oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is still in use today, principally in the far east. A modern abacus consists of rings that slide over rods, but the older one pictured below dates from the time when pebbles were used for counting (the word "calculus" comes from the Latin word for pebble).




Napier's Bones
In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier's Bones.

Definition of IT

From the  broadest sense, information technology refers to both the hardware and software that are used to store, retrieve, and manipulate information. At the lowest level you have the servers with an operating system. Installed on these servers are things like database and web serving software. The servers are connected to each other and to users via a network infrastructure. And the users accessing these servers have their own hardware, operating system, and software tools.


Beside this we can consider This Definition also


"The technology involved with the transmission and storage of information, especially the development, installation, implementation, and management of computer systems within companies, universities, and other organizations."