how an an anti virus program work?
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Аnti-virus software consists of computer programs that attempt to identify, thwart and eliminate computer viruses and other malicious software (malware).\n\nАnti-virus software typically uses two different techniques to accomplish this:\n\n    * Examining (scanning) files to look for known viruses matching definitions in a virus dictionary\n    * Identifying suspicious behavior from any computer program which might indicate infection. Such analysis may include data captures, port monitoring and other methods.\n\nMost commercial anti-virus software uses both of these approaches, with an emphasis on the virus dictionary approach.\n\nHistorically, the term anti-virus has also been used for benign computer viruses that spread and combated malicious viruses. This was common on the Amiga computer platform.\n\n=============================\nTechniques\n=============================\n\nVirus dictionary approach\n\nIn the virus dictionary approach, when the anti-virus software examines a file, it refers to a dictionary of known viruses that the authors of the anti-virus software have identified. If a piece of code in the file matches any virus identified in the dictionary, then the anti-virus software can take one of the following actions:\n\n   1. attempt to repair the file by removing the virus itself from the file\n   2. quarantine the file (such that the file remains inaccessible to other programs and its virus can no longer spread)\n   3. delete the infected file\n\nTo achieve consistent success in the medium and long term, the virus dictionary approach requires periodic (generally online) downloads of updated virus dictionary entries. As civically minded and technically inclined users identify new viruses "in the wild", they can send their infected files to the authors of anti-virus software, who then include information about the new viruses in their dictionaries.\n\nDictionary-based anti-virus software typically examines files when the computer's operating system creates, opens, closes or e-mails them. In this way it can detect a known virus immediately upon receipt. Note too that a System Administrator can typically schedule the anti-virus software to examine (scan) all files on the user's hard disk on a regular basis.\n\nAlthough the dictionary approach can effectively contain virus outbreaks in the right circumstances, virus authors have tried to stay a step ahead of such software by writing "oligomorphic", "polymorphic" and more recently "metamorphic" viruses, which encrypt parts of themselves or otherwise modify themselves as a method of disguise, so as to not match the virus's signature in the dictionary.\n\nSuspicious behavior approach\n\nThe suspicious behavior approach, by contrast, doesn't attempt to identify known viruses, but instead monitors the behavior of all programs. If one program tries to write data to an executable program, for example, the anti-virus software can flag this suspicious behavior, alert a user and ask what to do.\n\nUnlike the dictionary approach, the suspicious behavior approach therefore provides protection against brand-new viruses that do not yet exist in any virus dictionaries. However, it can also sound a large number of false positives, and users probably become desensitized to all the warnings. If the user clicks "Accept" on every such warning, then the anti-virus software obviously gives no benefit to that user. This problem has worsened since 1997, since many more nonmalicious program designs came to modify other .exe files without regard to this false positive issue. Thus, most modern anti-virus software uses this technique less and less.\n\nOther ways to detect viruses\n\nSome antivirus-software uses of other types of heuristic analysis. For example, it could try to emulate the beginning of the code of each new executable that the system invokes before transferring control to that executable. If the program seems to
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it gets viruses from the computer
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There are many free security programs available for download. \n\nAn anti-virus program is a must. If your PC came with Norton or McAfee anti-virus and you have NOT been updating the virus definition files your PC is at risk. If your subscription to Norton or McAfee has lapsed and you have not renewed your subscription so that you can receive virus definition updates then your PC is at risk.\nAn anti-virus program is only effective if the virus\ndefinition files are updated on a regular basis (at\nleast once a week). If you are cheap (like me) there is a good anti-virus program called AVG from Grisoft that is free for personal use.\n\nYou can download it here (link near bottom of page):\nhttp://free.grisoft.com/doc/2/lng/us/tpl/v5\n\nBefore you install this program be sure to UNINSTALL\nany other anti-virus program that you currently have\ninstalled. Anti-virus programs don't play well\ntogether so you should have only one anti-virus\nprogram installed at any given time.\n\nThere are 3 good FREE programs that are effective at dealing with spyware, Ad-aware SE Personal (removes spyware), Spybot Search & Destroy (blocks and removes spyware), Spyware Blaster 3.2 (blocks spyware). I have all 3 of these programs installed on my PC and they work well together without any conflicts. After these programs are installed they need to be updated on a regular basis to be effective. These programs will have to be manually updated.\n\nYou can download Ad-aware SE Personal here (click on "Download Now" near top left of page):\nhttp://www.download.com/Ad-Aware-SE-Personal-Edition/3000-8022_4-10045910.html?part=dl-ad-aware&subj=dl&tag=top5\n\nAd-aware SE Personal will scan your PC and\nidentify spyware that should be removed. Ad-aware\ndefinition files are updated about once a week.\n\n\nSpybot Search and Destroy can be downloaded here:\nhttp://www.safer-networking.org/en/download/index.html\n\nSpybot Search and Destroy will "Check for Problems"\n(scan) your PC for spyware that should be removed.\nBe sure to use the "Immunize" feature that blocks\nknown spyware from getting onto your PC. Spybot\nSearch and Destroy detection files are updated about\nonce a month.\nAfter you update Spybot Search and Destroy each month be sure to "immunize" your PC so that the updated spyware threats will be blocked.\n\n\n\nSpyware Blaster can be downloaded here:\nhttp://www.javacoolsoftware.com/spywareblaster.html\n\nAfter the program is installed be sure to click on\n"Enable All Protection" so the program blocks spyware.\nDetection files are updated about once a month. After updates are installed each month be sure to click on "Enable All Protection" again so the updated detection files are applied.\n\n\nYou may also want to use Mozilla Firefox as your\nprimary web browser. Firefox is an excellent program,\nand I have been using it for several months now.\nFirefox has fewer security flaws than Internet\nExplorer. You will still need to use Internet\nExplorer to download Microsoft updates.\nYou can download Firefox here:\nhttp://www.mozilla.com/\n\n\nBe sure you have all the critical updates from\nMicrosoft for Windows and Internet Explorer.\nOpen Internet Explorer, click on "Tools" and select\n"Windows Update", and download all the critical updates.\n\n\nYou also need a good firewall to protect your PC.\nWindows XP comes with a firewall. It's better than\nnothing but you need more protection. Zone Alarm Basic Firewall is a FREE firewall program that provides good protection.\n\nYou can download it here:\nhttp://www.zonelabs.com/store/content/catalog/products/sku_list_za.jsp?dc=12bms&ctry=US&lang=en&lid=dbtopnav_zass\n\nWhen you install Zone Alarm you will be prompted to\nchoose the free trial to Zone Alarm Pro or just Zone\nAlarm, choose the Zone Alarm (just the firewall)\nbecause it's free. Zone Alarm monitors incoming and\noutgoing transmissions. It will take a little e
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Hands down the best free antivirus program that I have used is AVG free, by Grisoft. Great updates, quick action too.
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Here you have some good and free antivirus programs:\nhttp://askcomputerexpert.ws43.com/download/\nI recommend Avast or Kaspersky.
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No PC is fully protected, I'm sorry to say this but it's true! \nReasons:\n1. first the virus program appears (attacks) and then the antivirus! (some antivirus software use recent bloodhound technology but it ususally gives many false positives so I don't recommend it)\n2. a simple spyware program only removes spyware! It doesn't protect you from it; for more security use a spyware active monitoring (like a firewall), but still this doesn't assure that you won't receive spyware (same as 1)\n3. of course there are programs that do it all, they are generally called Internet Security package and it's said that they should do all the work!
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There are many decent anti-virus programs available. Norton's is one of the best, as it's both thorough and economical and doesn't use up a lot of memory; however, the problem where memory is concerned is that the best programs require the most memory. I was using Nortons awhile back and still got a virus, so I spent about $300.00 on a very extensive program called Tech on Demand. Unfortunately, it requires a lot of memory to run because of the many functions of the program. The amount of memory is pretty much proportional to the amount of protection you're looking for.
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For the BEST FREE AntiVirus Program, download it from here:\nhttp://free.grisoft.com/softw/70free/setup/avg71free_375a716.exe\n\nAVG AntiVirus FREE VERSION
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Hi there,\n\nMost antivirus programs use something called "signatures" to protect their users.  These are files which their research team create in order to protect your computer from each infection by basically "patching" a hole in your system.  These are what are downloaded when you perform an "update".\n\nHowever, this is a very outdated technique and is being abandoned by forward thinking security programs.  One such program which I use and recommend is Prevx1.  This program requires ZERO updates, yet your protection capabilities are being updated every second of every day. Outdated programs which require you to download signatures means you could be unprotected for days or weeks why a member of their research team creates a fix for you to download.  Prevx1 works in a completely unique way, meaning if any person with Prevx1 installed on their computer discovers a new infection, it is automatically blocked from running. The best part however, is that Prevx then informs their online malware database which instantly protects every other user in the world with Prevx1 installed.\n\nVery Clever.
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You can only use one antivirus program or you will have conflict with your system..  You don't say what antivirus program you have, but it is obvious it is not working for you.  So remove it an install Avast.\n\nIn my spare time I test on my backup computer all antispyware/antivirus programs to see if the perform as claimed And especially to see which one have embedded trojans/adware either in their program or in the wizard installer used to guide you through the installation. \n\nWhat is rate as 1-2-3-4-5 is not always the best. Especially when you can find free programs that are light years ahead in technology over the purchased.\n\nIn my computer I use the following free programs.\n\nFor antivirus you can only use one or you will have serious conflict with your system. You can use three or four antispyware without any conflict.\n\nAvast in my opinion is the very best. Have you Avast for nine plus years and never had one virus. They are out of Prague.\n\nhttp://www.avast.com This program is free and has one of the very best background scanner that will catch any virus in real time and destroyed the virus before it can enter you system. \nUpdates auto., two or three times per day. They will ask you for your email address so they can send you a free key that is good for one year. After one year you only have to request a new key.\n\nClinical Psychiatrist, France
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It doesn't do much good to just run the Anti-Spy and expect it to remove the infection. There is a procedure you need to follow to get it clean out. The writers of this malware know how to hide these things so the AS and AV programs can't remove them with the normal process. Go to this site and it will walk you through the correct procedure. This same procedure can be used with Anti-Virus software if needed.\n\nhttp://www.microsoft.com/windows/IE/community/columns/bugbusting.mspx\n\nAfter doing the above please go here and read about Malware and you will come away very informed about how to protect your computer.\n\nhttp://www.internetinspiration.co.uk/computer_privacy_and_security.htm\n\nNow go here and download Cyberhawk. It will work with you AV/AS programs. Do not use as stand alone AV/AS protection. No setup required. Just download and let it run.\n\nhttp://www.novatix.com/News.aspx\n\nIf you do not have an Anti-Virus program please go here and download AVG 7.1. the update it. There will be a link in the program to do updates. You will find it in the 3rd red box down.\n\nhttp://www.filehippo.com/\n\nOne AS program is not enough as you will learn when you read the above site. Please go here and download Windows Defender. It is very good. Its the last item in the first red box.\n\nhttp://www.filehippo.com/\n\nEverything I given here is Free with no strings attached and is better than most of the stuff you pay for.
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Four programs, yes, all four of them (Google them):\n\nAdaware SE Personal\nSpybot Search and Destroy\nMS AntiSpyware Beta\nSpywareBlaster\n\nIf you are also interested in free antivirus software check out AVG Free, http://free.grisoft.com/
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The list of anti-virus proggie grow every day.  New companies are getting into the internet security business, all claiming to be better than one another.  I repair PCs for a living, and I deal with virii and spyware on a daily basis.  It is a big help to me to be able to have programs at my fingertips that will help me get the job done.  The top 4 names are:\nNorton\nMcAfee\nAVG\nAvast!\n\nHere's how they break down, in my experience:\nNorton-  This is an okay product if you have a very powerful computer.  It's removal ability is great, but it sometimes lets things slip by unnoticed.  Very slow in safe mode, which is the ideal way of removing an infection that is already on the computer.  There is a cost for the license.\n\nMcAfee-  This product is average in every way.  Nothing outstanding about it, but it is still better than Norton...barely.  Again, tough to run in safe mode.  Uses a lot of resources.  There is a fee for renewing the agreement.\n\nAvast!-  has a free edition.  It is one of the better suites availible for free.  The pro edition is well rounded and very trustworthy.  Runs pretty well in safe mode.  Great detection, and removal.  The pro edition has a license fee, but it is actually worth paying for.  Maybe the 2nd best in the PC world.\n\nAVG- The free edition of AVG is the number one anti-virus program in the world for one reason alone:  IT WORKS!!!  It is the easiest to operate, the fastest, most thorough and works as well in safe mode as it does in active mode.  The updates are free forever.  There is also a pro edition which put a few more excellent tools at your fingertips.  There is a cost for pro, but like Avast, it is well worth every dime you spend.  \n\nThere you have it.  But, a few points to ponder before I go:  Any anti-virus software will be dramatically improved by your surfing habits.  Things like not allowing active script to run, accomplished in Internet Options>advanced.  Always type in the addresses in your browser instead of clicking links in your email.  Watch where you surf, and how you download from Peer-to-Peer networks like Gnutella.  I would suggest as your first move to switch your browser to Mozilla Firefox.  I have NEVER contracted a virus while surfing since switching to Firefox, and neither has anyone that I have switched to it from the "Big Blue E".  Good luck, and happy surfing!
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I would start the answer by the famous quote, "Why do computers get viruses. They're little boxes. They shouldn't." ~ Janelle\n\na virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. A computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of a virus into the program is termed as an infection, and the infected file (or executable code that is not part of a file) is called a host. Viruses are one of the several types of malicious software or malware.\n\nn 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.\n\nCheck out this movie on Virus replication :\nhttp://video.google.com/videoplay?docid=9192961636386984286&q=computer+virus\nhttp://video.google.com/videoplay?docid=-7821323279275205551&q=virus\n\nALso check out the movie ANTIVIRUS:\nhttp://video.google.com/videoplay?docid=3481400607478146088\n\nThe best Antivirus to prevent Virus Infection is Norton Antivirus, but it is heavy on system and is generally in 60 day trial version forms. I personally like Avast, because it is light weight and is free.\n\nI have a few Free Antivirus programs I can reccomend:\n\nhttp://www.avast.com/ avast!\nhttp://www.free-av.com/ AntiVir HBEDV\nhttp://free.grisoft.com/doc/ AVG Free Edition\n\nAlso, if your willing to experiment:\nhttp://www.microsoft.com/windows/onecare... Windows OneCare Beta\n\n\nThe best resource for antivirus:\nhttp://www.faqs.org/faqs/computer-virus/alt-faq/part1/\nhttp://www.faqs.org/faqs/computer-virus/alt-faq/part2/\nhttp://www.faqs.org/faqs/computer-virus/alt-faq/part3/\nhttp://www.faqs.org/faqs/computer-virus/alt-faq/part4/
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Neither program has a very high virus detection rate. Expect them to not detect about 10% of all viruses. Some paid solutions such as Kaspersky miss less than one half of one percent.\n\nThat being said I use Avast (you can't beat the price). And it uses about 15 to 18 mb on my comp.
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Antivirus softwares are only effective if you update them daily.Even then the computer is still vulnarable because the antivirus cannot detect threats from viruses that was made just 5 minutes ago and released on to the net.\n\nAntivirus sometimes itself can act strange(ex:it will detect its own files as viruses, try to clean them and get corrupted).Sometimes Antiviruses takes up a lot of RAM (as it has 4 to 6 programs of itself running in the background) This may cause freeze.\n\nMost viruses are designed to work in background pulling as much less RAM as possible and if it has a smart programming it will mix itslef with Your Files on the Hard Disk.\n\nI suggest goto run > type: sfc /scannow \nThis will repair some win files damaged by viruses.
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theres no software used as such- you can create virses in any programming language so long as you have a sound understanding of the operating system or browser. antivirus software works by looking for a specific signature code of a virus.