All about computer viruses and the most common symptoms

Name: My computer can catch a cold...?
Category: Viruses/Spyware
Operating System: All but Windows systems are much more likely to be effected
Difficulty: n/a

So what are viruses...?
Even if you are smart with the websites you visit and the stuff you download then you will probably still have had a problem with a virus at some stage. Viruses are the scourge of the Internet, but they have been around for a lot longer than that. A virus is basically a malicious computer program designed to spread via various methods. Closely related to viruses are trojans and worms, which for the sake of this article are basically the same thing.
(if you really want to know, worms spread themselves to other computers without needing to be transferred as part of a host, and a Trojan horse is a file that appears harmless until you use it!)

What are the symptoms...?
Just like regular viruses the symptoms of computer viruses are always different and just because you notice one of these things it doesn't mean you necessarily have a virus. Spyware can also have many of the same effects.
Symptoms may include:

• Your computer runs slower than usual.
• Your computer stops responding, or it stalls frequently. Maybe even displays a blue screen
• Your computer crashes, and then restarts every few minutes.
• Applications on the computer don't work correctly.
• You notice unusual error messages.
• You notice distorted menus and dialog boxes.
• Your antivirus program is disabled for no reason and cannot be restarted.
• An antivirus program can't be installed on the computer, or the antivirus program will not run.
• New icons appear on the desktop that you did not put there or ask to be put there from recently installed programs.
• Files, folders and programs disappear from the computer even though you did not remove them.
• Your hard drive is accessed too often (the hard drive light flashes rapidly).
• Windows will not start at all or starts with many error messages.
• Your modem is still sending and receiving files (lights flashing) even when you are not using the Internet.
• Your email contacts mention that they have received messages from you but you never sent such messages.
• Your mailbox contains many messages without the sender's email address or header.

To be honest there are many more than this so you should be watching for any unusual behaviour from your computer.

I think I have a virus what do I do...?
Firstly don't panic. Then if you don't have a virus scanner download a good free virus scanner (I will give you a list at the end of this post). Make sure you update the virus definitions and scan your computer. If the scan detects anything quarantine or remove the infected files and restart. Most times after doing this all will be well (especially if it wasn't a serious virus). If you are still having problems then consider doing the following:

• If you can't start windows or the virus seems to keep coming back try running the scan in safe mode (enter safe mode by repeatedly pressing the "F8" key as/before the operating system boots).

If you are still having trouble consider getting a professional to look at it for you. It might cost a fair bit, but they should know what they are doing and your computer just might come back to you in better condition than you remember it. Ask people for advice as most people have had good/bad experiences with a local computer repairman.

Recommended free virus protection/detection programs (follow the links to download):
AVG free - A fairly good detection rate and most people will be able to use this. For what it is worth I use this one. They also offer a free anti spyware program
AVAST 4 - Another decent free virus scanner. Many people like this one I find it a little obtrusive.
AntiVir - Another popular free anti virus software. I did use this, but switched to AVG for some unknown reason (ie. I can't remember why!)
Bitdefender - Free anti virus for linux users
ClamWin - open source virus scanner for Windows
Comodo antivirus - Must admit I hadn't heard of this until I wrote this article. It looks promising and is 100% free

Should I pay for "better" protection...?
In my opinion no, but if you are really worried or spend lots of time on questionable sites then maybe. I think that most of the free programs have acceptable rates of detection and in some cases outperform more expensive alternatives.

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