If you find certain strange things happening in your Computer, it may be an indication of a virus intrusion. For example, some text on your screen seems to be missing, or the performance of your PC has suddenly degraded, or the file sizes have suddenly increased. These are signs that the virus or some malicious software has intruded into your PC system.

The general term ‘Virus’ indicates a destructive germ. In Computer terminology, however, a virus is a short program which causes destruction to other programs on the Computer. A virus is a piece of software written by some programmer who intends to cause harm to the Computer Systems.

The term ‘Virus’ has acquired the status of a general term to describe any malevolent program that causes harm to the Computer system, however, besides viruses, there are many other types of malevolent programs which can cause problems in the normal functioning of the PC. In this Article we will describe various types of malevolent programs that may intrude your PC, the harm they can cause to your PC, the methods by which you can protect your PC from these intrusions and the ways of detecting and eliminating these malicious programs.
 
Types of Malevolent programs.

1. Trojan Horses .

A user installs a certain program into his computer thinking that it is an application program such as Word or Excel, but actually this harmless looking program is a malevolent software known as the Trojan Horse. Hence, you should be careful to install any software which promises to perform things which are spectacular. The Trojan horses spread viruses after they are installed into your system. Hence, you must first scan a software thoroughly for viruses and only then install it into your PC.

2. Software Bombs.

The software Bombs explode when the software is executed on your PC. It spreads the viruses into your Computer system. These programs can be detected by the antivirus softwares.

3. Worms

A worm has the tendency to attack a group of computers rather than a single computer. The worm travels on the network, attacking various Computers connected to the network.
A worm can destroy passwords or specific types of files on the Computer system.

4. Virus.

The most dangerous of all malicious software is the Virus. There are many types of viruses. Some viruses infect the command processor of the operating system, some viruses infect the Boot sector of the hard drives, some viruses infect the executable files on the PC, while some viruses cause harm to specific file types. Some viruses employ the stealth tactics to gain entry into the system and then destroy the valuable data in the system.

Preventive methods of Protecting the PC against the Virus attacks.

1. Use of firewall.

When your Computer is connected to the internet there is every possibility that the malicious programs such as the viruses, Trojan horses, worms etc may enter your PC.
The firewall is a software which protects your Computer system against attacks by the computer viruses and prevents their intrusion into your Computer system. The firewall gets automatically installed alongwith the Windows Xp operating system. It protects your Computer from attacks by malicious programs from the internet. You can also install separate firewall software, apart from the one provided by the Window Xp. The firewall is not the same as the Antivirus software and it cannot detect and destroy the viruses.

2. Backup of data

It is always safe to backup your data, before it is destroyed by the malevolent programs
You should make the habit of taking daily backup of your data, as it may be too late before you realize that your important data has been destroyed by the viruses.

3. Scanning.

Before downloading any program or files from the internet it is advisable that you scan the program or the files and download the files only if they pass the virus test. The seemingly harmless programs and files may contain malevolent software.

Every attachment from the email should also be checked for virus before being downloaded into your PC. There is great tendency to send viruses through harmless looking emails, hence, extra care should be taken when downloading the email attachments.

Detecting and destroying the Virus.

A virus may be detected by the use of the Antivirus software available in the market, such as the PC Clean and the Norton Antivirus. These Antivirus software scan your PC for viruses and other malevolent programs and display the list of the same. However, new viruses are developed by programmers each day and your Antivirus software may not have the capacity to scan and destroy every type of virus. Hence, it is necessary to update your Antivirus software with the latest information from the database of the viruses, by connecting to the website of your Antivirus Software.

The Antivirus Software can destroy the viruses detected in your PC. On giving the command the Antivirus Software scans each and every infected file in your PC and destroys the viruses.

There is also an option in the Antivirus Software to inoculate your PC against the virus attacks. After inoculation, a virus attack is reported instantly and action can be taken to destroy the same.

Proper knowledge of viruses and malevolent software will help you to keep your PC, as well as the network, safe and secure. If you know what type of viruses can attack your PC, how to detect virus infection and how to destroy the viruses you can protect the software and data on your PC from being destroyed and lost.