few questions that are asked the most and an attempt to answer them the best I can.  Some of the

answers are quotes or answers from all over the internet, but these are some of the best answers

I can find.  I hope that this answers some questions.  

• What is a Virus?

• Definition:

  "A parasitic program written intentionally to enter a computer without the users permission or knowledge. The word parasite is used because a virus attaches to files or boot sectors and replicates itself, thus continuing to spread. Though some virus's do little but replicate others can cause serious damage or effect program and system performance. A virus should never be assumed harmless and left on a system." -Symantec

   

  A functional definition of a computer virus must include the fact that it creates damage to the computer system "infected"; either inadvertently or deliberately. This definition is somewhat simplified and does not cover all virus types, but is sufficient to show the major differences between viruses and so-called "Trojan" programs, which is that the virus replicates, but the Trojan program does not.

   

• What is Spyware?

• Spyware is software or hardware installed on a computer without the user's knowledge which gathers information about that user for later retrieval by whomever controls the Spyware.

  Spyware can be broken down into two different categories, surveillance Spyware and advertising Spyware.

  Surveillance software includes key loggers, screen capture devices, and Trojans. These would be used by corporations, private detectives, law enforcement, intelligence agencies, suspicious spouses, etc.

  Advertising Spyware is software that is installed alongside other software or via activex controls on the internet, often without the user's knowledge, or without full disclosure that it will be used for gathering personal information and/or showing the user ads. Advertising Spyware logs information about the user, possibly including passwords, email addresses, web browsing history, online buying habits, the computer's hardware and software configuration, the name, age, sex, etc of the user.

  As with spam, advertising Spyware uses the CPU, RAM, and resources of the user's computer, making the user pay for the costs associated with operating it. It then makes use of the user's bandwidth to connect to the internet and upload whatever personal information it has gathered, and to download advertisements which it will present to the user, either by way of pop up windows, or with the ad banners of ad-supported software. All of this can be considered theft in the cases of advertising Spyware that installs without disclosure.

   

• What is a Highjacker?  or Hijack browser or Hijacker

• A browser hijacker (sometimes called hijackware) is a type of malware program that alters your computer's browser settings so that you are redirected to Web sites that you had no intention of visiting. Most browser hijackers alter default home pages and search pages to those of their customers, who pay for that service because of the traffic it generates. More virulent versions often: add bookmarks for pornographic Web sites to the users' own bookmark collection; generate pornographic pop-up windows faster than the user can click them shut; and redirect users to pornographic sites when they inadvertently mistype a URL or enter a URL without the www. preface. Poorly coded browser hijackers -- which, unsurprisingly, are common -- may also slow your computer down and cause browser crashes. Browser hijackers and the pornographic material they often leave in their wake can also be responsible for a variety of non-technical problems. Employees have lost jobs because of content and links found on their computers at work; people have been charged with possession of illegal material; and personal relationships have been severed or strained. In one case in the United States, a Russian immigrant was convicted for possession of child pornography, although he claims to have been the victim of a browser hijacker. Like adware and Spyware, a browser hijacker may be installed as part of freeware installation. In this case, the browser hijacker is probably mentioned in the user agreement -- although, obviously, not identified as a browser hijacker. The problem is that users typically either ignore the fine print or only give it a cursory reading. A browser hijacker may also be installed without user permission, as the result of an infected e-mail, a file share, or a drive-by download. To avoid contamination, experts advise users to read user agreements carefully, and to be cautious about freeware downloads and e-mail messages from unknown sources.

• What is Malware?

• Malware (for "malicious software") is any program or file that is harmful to a computer user. Thus, malware includes computer viruses, worms, Trojan horses, and also Spyware, programming that gathers information about a computer user without permission.   This new strain of viruses are deadly and there are few antivirus programs out there that will find them or clean them many time you do not even know that they are even on your computer. Thus Malware is dangerous to you and to all your friends.

• What is freeware?

• 
   

  Freeware (not to be confused with free software is programming that is offered at no cost and is a common class of small applications available for downloading and use in most operating systems. Because it may be copyrighted, you may or may not be able to reuse it in programming you are developing. The least restrictive "no-cost" programs are uncopyrighted programs that are in the public domain. When reusing public domain software in your own programs, it's good to know the history of the program so that you can be sure it really is in the public domain. Free software, a somewhat newer and unrelated concept, is software that can be freely used, modified, and redistributed with only one restriction: any redistributed version of the software must be distributed with the original terms of free use, modification, and distribution (known as copyleft). The definition of free software is stipulated as part of the GNU project and by the Free Software Foundation. Unlike freeware, free software may be distributed for a fee. Freeware is liable to be more limited in capability than free software.

   

   

  
   

• What is drive-by download?

• A drive-by download is a program that is automatically downloaded to your computer, often without your consent or even your knowledge. Unlike a pop-up download, which asks for assent (albeit in a calculated manner likely to lead to a "yes"), a drive-by download is carried out invisibly to the user: it can be initiated by simply visiting a Web site or viewing an HTML e-mail message. Frequently, a drive-by download is installed along with another application. For example, a file sharing program might include downloads for a Spyware program that tracks and reports user information for targeted marketing purposes, and an adware program that generates pop-up advertisements using that information. If your computer's security settings are lax, it may be possible for drive-by downloads to occur without any action on your part. Xupiter, an Internet Explorer toolbar program, is frequently installed as a drive-by download. The program is said to replace the user's home page, change browser settings, and use redirection to take all searches to the Xupiter Web site. In some versions, the program initiates drive-by downloads of other programs. Furthermore, although it comes with an uninstall utility, Xupiter is said to be next to impossible for the average computer user to remove. There are some arguments to be made in favor of drive-by downloads, particularly for downloads of patches or service packs that address security flaws. If these were automatically installed, instead of depending on the diligence of server administrators, computers and the Internet in general might be safer from malicious programming such as viruses and worms. In January 2003, a worm called the SQL Slammer exploited a known buffer overflow vulnerability in Microsoft SQL 2000 server systems to cause widespread Internet outages. The attack was launched precisely six months after Microsoft released a patch for the flaw. If the patch had been installed to vulnerable systems, the attack would have had little impact. However, although drive-by downloads for patches might address specific security flaws, they might also conflict with existing system configurations, and thus create more problems than they solve.