Most people are now familiar with the threat that viruses pose to their PCs, but an invasion of another type of unwanted software, commonly referred to as "spyware", could be equally destructive.
Spyware is a general name for a large group of unwanted software that is downloaded and installed in the computer without the knowledge of the computer user. This type of software could range from rare innocent cookies, which keep track of what websites one has visited, to software that records key-strokes, and then sends this information back to the people who installed it, to enable them to extract information such as passwords, credit card numbers and other very sensitive personal information.
The large majority of spyware that is commonly installed on people's computer is what is termed "adware". This is most often a piece of information in the form of a cookie, which enables the sender to display advertisements on the computer in the form of pop-up ads. These ads can become quite annoying, but are generally not harmful to the operation of the computer.
Another type of cookie that is very common keeps track of the website one has visited, thus enabling website operators to display ads to the person browsing their site, specific to the type of preferences that person browsing the sites has displayed in the past. Such cookies allow the websites that you frequently visit, to 'remember' your preferences, your name, user ID or other information, which may identify you as a returning frequent visitor.
This type of personal information is generally stored in a specific subdirectory or folder on the hard drive and can be reliably easily removed, either by yourself or by your web browser, which may have a "delete cookies" button in one of the menu options.
Some more invasive types of software that can be installed on your computer without your knowledge are capable of changing your computer settings or preferences, such as installing toolbars, or modifying the default website setting in your browser. Usually these types are referred to as "spyware" and are much more difficult to remove. The most obvious signs of a spyware infection may be the sudden appearance of pop-up ads for items or sites you have no interest in at that time and are not related to what you are doing, such as gambling or adult sites.
Frequently spyware and related nuisance software is introduced to your computer during installation of software that you actually want, but then somewhere hidden in the installation procedure is a message, or if you are lucky a button to select the option to install it. However most of the time this option is so well masked or tucked away at the end of the installation process, that most people do not notice it and then inadvertently install this spyware as well. Toolbars and unwanted utilities are an example of this.
It is there though regularly advised during installation of software for certain tools, utilities or other applications, such as browsers, free software, audio or video software or other such specific applications, to pay particular attention to any selection options, such as boxes with tic- marks or radio-buttons, and make sure you know what you are installing. If you are not sure that you want that option, or you are suspicious about it, make sure to de-select the option. You can safely do this, since if you are presented with an option to deselect it, it is not a requirement for the proper operation of the software anyway.
The most dangerous type of spyware, also referred to as "malware", is installed on the PC without any warning at all.
This is the type of software that could collect keystrokes from your computer (key-logger), to be used for credit card fraud or even identity theft. Another type could be dial-up software which uses a modem dialer to dial out to some number that charges outrageous fees for being connected etc.
Many of these types of software have components installed in obvious places, such as the Program Files folder, but then also have components installed in much less obvious places such as the Windows system files or the registry where they are very hard to find or recognize. Therefore if you were to remove the software from the Program Files folder, it would re-install itself and re-appear when the system is rebooted. For most people the only way to get rid of this nuisance software is to avail himself or herself to the assistance of either very specialized people or software, which is designed to do this for you.
It is there recommended that next to your anti-virus software, you also install an anti-spyware or anti-adware program on your computer, and make sure that the software provider also updates this software regularly. Letting such programs do their work on a regular basis will keep your computer clean and could prevent some nasty experiences, something we all could live without.