What is a Virus and how do I know if I have one?

If you are asking “What is a virus” then it is very important that you read through this article. There are some obvious symptoms that your computer will develop when it gets infected with a virus and to recognize these, you need to know what a virus is. But the first thing I have to mention is that if you had a decent antivirus program installed on your computer you would not have a problem. The virus programs now days are fantastic in crushing any chances of a viruses infecting your computer. There are many ways to protect your computer from viruses, however, knowing what a virus is should be your number one priority.

What is a virus?

What is a virus is a very important question! A virus is a small program that gets into your computer undetected in order to cause havoc. This small software program has either been developed because the author enjoys causing disasters for other people or sometimes for monetary gains. Sometimes a virus is packaged in a file that is called a trojan virus. It is disguised as something else, and once it has gained access to your computer it then releases its intent.  Also see What’s the difference between a virus, spyware, Malware, and adware?

Here are some more technical definitions relating to what is a virus from other websites:

Wikipedia – what is a virus?

Microsoft – what is a computer virus?

What is a virus and how does it get onto my computer?

The people that develop these viruses are constantly finding new ways to infiltrate your computer. When one door shuts, another one opens for them. However the most common ways to get a virus on your computer is through the internet. You might download a file that contains a virus, or maybe you might open an email that has one attached to it. Sometimes even visiting a bad website can infect your computer. The worst one of all, however, is when people download illegal cracked software. This software has usually been taken apart and repackaged with a few extras attached. Maybe you download music or videos from the internet. How do you know you are actually downloading the file you intended to. The file may be named to deceive you, and once you open it you will release the virus.

Another common way to get a virus is to see software appear on your screen that is posing as an antivirus program. The minute you press the cross button to close the program or even the scan button, because it is telling you to scan for viruses, you are immediately infected by this virus. If you see a program come up on your screen that you know you did not install, the best way to shut it down is to open up task manager and end the process.

How do I know if I have a virus or not?

If your computer has been infected with a virus you will quickly see odd signs that it exists. Weird things start happening that you cannot explain. Files might move around, odd error messages may appear, programs might start to fail. For example if your virus scanner program stops working then it could have been disabled by a virus. With all this action taking place in the background your computer will also start to run slow and seem like it is busy all the time.

When browsing the internet you might find that you will not able to visits the pages that you choose. You will be redirected to different websites. You computer might also be sending emails to everyone in your contact list without you knowing.

What can a virus do to my computer hardware components?

People think that a virus simply attacks the file systems of your computer, however this is not true. Some viruses are designed to damaged computer hardware components until they are ruined completely.

Many people will argue that a virus only infects software, however all hardware is controlled by various types of software. Infact the entire computer is controlled by BIOS which is software. BIOS controls the temperature of the motherboard. What if a viruses only purpose was to change the temperature control on your motherboard. The motherboard would overheat and fry itself.

In the old days viruses used to be developed to set the read speed of a floppy disk drive to speeds beyond its capability. The Floppy disk drive would overheat and fry from being overworked. Now days Windows Vista has a service called Superfetch that searches your hard drive, finds out what you use the most, and makes it available for you.. If you made a virus to control Superfetch, we could have a serious problem. Most Vista users already have Superfetch disabled on their computer. A virus could enable it, tell it all files are important, keep it searching non stop, and fry your hard drive that way. Now I can here someone saying “yeah right, not with all the security we have around today”. Well you should never underestimate these guys who develop viruses. They can work around anything.

What should I do if I get a virus?

If you suspect that your computer has a virus, scan your computer asap with an antivirus program. If you do not have one or yours is not working, download another one, or get a free scan using the free online virus scanners.

Here is a list of free online virus scanners.

Symantec Security Check, McAfee FreeScan, Panda ActiveScan, Trend Micro, Kaspersky lab, bitdefender, and there are so many more. There is no guarantee that these free scanners will cure your computer but they might just confirm the fact that you actually have a virus.

If you find viruses but cannot remove them you will need to take your computer to a professional before you lose everything. Another option is to format your computer which means you loose all the files on it and re-install a fresh copy of the operating system. You can backup your files first, but please be aware that they might be infected with a virus also.

If you have scanned your computer, found viruses, and successfully deleted them, then now is the time to buy a decent program that will stop this from happening again. See my review of the best Virus Removal Software.

Do not continue to use the computer without taking action because the longer you leave it the further the virus can spread.

What is a virus? What file types commonly contain viruses?

Lets face it, downloading is a dangerous business, especially when you have important files stored on your computer. Any file you download can contain a virus. My rule for downloading is to ask myself “Do I know and trust this website I am about to download from?”

Here are a few examples of common files that could contain viruses:

EXE FILE: If you download a program or anything that requires an install file then it will be an .exe file. When you press on it to install to your computer you could be releasing a virus.

ZIP FILE: People download zip files from the internet that contain any other file type and you will not see it’s contents until you open it. A zip file might have an exe file in it.

SCR FILE: Free screensavers for your computer. They always have something bad in them. Sometimes adware or viruses.

DOC FILE: A Microsoft word document can contain macros and small scripts that are viruses.

If you haven’t got antivirus software installed on your computer you should try Avast. It also takes care of spyware, malware, etc and it is fantastic! You do not have to worry about setting it up because it just stops all problems for  you and you will never know it is working away in the background.

Notes on what is a virus:

  • There is a lot of confusion about actually “what is a virus” because there are so many different types of viruses out there.
  • Most, if not all websites on the Internet agree that a virus is a small piece of software that invade your computer.

I hope you are not still asking “what is a virus” as this can be a very dangerous question.


  1. Themba Ndlazi says

    Its amazing how the virus works. I just suggest that It should be wise and save time and money if computer manufactures can intall or create an anti virus software that will be part an parcel of the Computer before anyone buys it. In other words a pre installed software that will last lifetime of the computer. It should be a tried and tested software or a program. So by so doing customers and computers users will be stress free while working with their computers. Recently someone told me that he can see an the virus file without scanning and he told me how easy is it to check that file. Can we have one antivirus software that can last computer life time?

  2. Ryan says

    Question, If my daughter was on a website and a fake virus alert popped up that she thought was real and clicked on the button that says run scan and it downloaded the zip file to the download folder but it was never clicked on is she in trouble? I deleted the file the second it downloaded…

    • says

      IF you have a virus program then use it to scan your computer. Also try a free online scan. You cannot be sure it did not infect something. I use Avast paid version and it would not even let anything popup like that.. It does not let me enter a website that has a virus. Prevention is always better than cure..

  3. says

    As your computer has virus it will work so slowly !!!
    And always you meet the errors. As setting up a new programme, you won’t do that !?
    Check :
    – Right-click on “My Computer”, select “Explore”, click on “Tools”, select “Folder Options”, choose tab “View”, make sure that the two sentences “Show hidden files and folders” and “Don not show hidden files and folders” are still there !
    – Push “Ctrl + Alt + Delete”, check the CPU Usage, it must be from 0% to 20% as no programme runs
    Sometimes you can destroy all of viruses but sometimes you can’t. In another cases, after destroying viruses, your PC still doesn’t work. So it’s the best way for you to re-setup the system at that time.

  4. says

    People should be aware that downloading files from anything other than the most trusted sources is a fast-track to loading a system with threats.

  5. hunter says

    what if i am running in safe mode because im doing that right now and the virus i have and i know i have i dont know what it is like a worm trojan or other but i went to bestbuy and they said this is a new virus well what happens is that i go into normal mode and after 5 minutes it starts to freeze and do random stuff like things pop up so can u help me with this please….!!!!!!!!!!!!!!

    • ashvir sidhu says

      try turning your computer on blank mode (delete wallpaper) or try saving your IMPORTANT files onto a USB and then reseting your computer to factory settings it works

  6. says

    Nice information . I could understand the meaning of virus.I totally rely on my anti-virus program. Nowadays hackers are even posting links to bad sites in facebook just to spread the virus. Users need to be careful.

  7. Sarah says

    I’ve been using Avast for quite some time, until recently when I updated it. Apparently Avast seems to be getting quite large, in terms of how much space it takes up. I think over 200MB installation for an anti-virus program is a bit much, which is why they could’ve left certain features I believe are unnecessary fo most home users. With that said, I’ve switched to Avira which has always worked just as good for me. Avast is greatly recommended, if you don’t mind having all the great features, and the huge installation that comes with it.

  8. Mika Castro says

    Hi! I enjoyed reading your post as it helps me to discover viruses that appears on my desktop. I have encounter many viruses from my computer and it is really hard to remove. You must format it to completely remove the infected file.

  9. jaishree says

    i am jaishree i read your tips to protect computer from virus,but i am not having good knowledge to maintain my computer so i want to know basic steps,how to protect my comp from virus and other problems.is there any anti virus software to remove virus without changing operating system?

    please give me guidance,i hope you will help me,please send a mail……..,

  10. star says

    dell vostro 1510 vista ,my internet explorer got from good to bad to worse little by little by little and by now doesn’t respond anymore ,i did at that time malawarebytes and drwebcure express scan and showed I’m clean when I did reset internet explorer everything got perfect but last only one day so ,when I completed spybot everything got almost perfect and again lasted only one day ,so I began to use Google chrome ,after week my word stopped to respond as normal and bunch pop up massages about macros and more ,I did restore point and got it back function but got one site always pops up at opening Google chrome and the speed is not as used to be ,I did now drwebcure complete scan and it showed 4 Trojan start page 1505 ;what’s that ?what’s for me to do about it ?I had trouble to exit drwebcure I had to log off in order to get it off the screen ,although I tem put user control off still can’t delete a fragment left from uninstalled avira antivirus it tells me I need administration rights ???drwebcure says that if I did the scan with no admin rights than system folders were skipped,

    • says

      Unfortunately I do not recommend relying on free programs to protect your computer. Apparently this Trojan, the “start page 1505” is a problem that DRWebcure has. Please see this forum post for an example: http://www.wilderssecurity.com/showthread.php?t=161793

      It does sound like you have other problems as well but for starters, I would uninstall that program and look for an all-rounder protection program or Internet security program such as Avast.