Where do computer virus myths come from? It’s hard to say. One minute you think you know how they work, and the next you’re being told you can get viruses from cookies, Javascript on Web pages, viewing GIF files, and so on. All nonsense of course, but it’s understandable to feel concerned. And it’s a lot healthier than completely assuming you’re safe from computer viruses, because unless you get rid of your PC that certainly isn’t true.DefinitionsA virus is a computer program that is designed to enter PCs without the user’s knowledge, then replicate itself throughout the system. Some viruses carry a ‘payload’ which activates eventually – this can be anything from displaying a silly message on the screen to wiping out all the files on your hard disk.An important step to protecting yourself is to realize when programs are running on your PC, because viruses can exploit them all. The first opportunity occurs when you switch on your computer. Both floppy disks and hard disks contain a little ‘boot sector’ program, which either displays a ‘you can’t boot from me’ message (on a normal floppy), or loads your operating system (on a hard disk). Boot sector viruses infect this program, so loading into memory every time you start your PC, then copying itself to every floppy disk you read.Other viruses target files containing program code; every time you run the infected program, it loads itself into memory, then might copy itself to other programs. Not just .exe files, either – .com, .dll, .ocx, .drv, .sys, and so on, are all at risk. After copying itself the original application continues to run and you never realize there’s a problem, until the payload hits you.Still, at least data files are safe, right? Wrong. Many Microsoft programs enable files such as Word documents and spreadsheets to contain program code (macros). This is great for automated office applications, but also presents another risk point. Just viewing a document carrying a macro virus can be enough to infect your whole system.Don’t PanicAlarmed? You should be, but there’s no need to panic. Modern antivirus software has some powerful features to prevent you getting infected. Two methods are particularly common.The first involves maintaining a table of virus signatures – sequences of bytes that occur in the virus program itself. Scan a downloaded file, and if you find that signature then you know the file might be infected. The signature approach is useful and quick, but can give false alarms if the signature occurs innocently somewhere. It’s no use on new viruses that aren’t in the signature file yet. And some viruses are polymorphic, meaning they change their own structure and just don’t have a consistent signature anyway.Fortunately the best antivirus software has another weapon in its arsenal – the heuristic approach. This involves looking for virus-like behavior – writing to an executable file, perhaps, or copying information to the boot sector. It’s a clever idea, and can even help detect completely new viruses.Protect YourselfInstalling good antivirus software is a great idea, but it’s only the first step. There are lots of other things you can do to help protect yourself. First you need to keep the software updated to cope with new threats. Some antivirus programs can update themselves automatically, but it’s still worth visiting the author’s web site every week to find out what’s going on. And don’t forget about the security settings on other software.There will always be some risk from viruses, but good antivirus software, combined with regular backups, should mean you can recover, if the worst happens.

This article is based on my own user experience of free and paid Internet security software. The free software I used consists of Sygate firewall, AVG antivirus, Ad-Aware Free Edition, Spyware Doctor and SpyBot Search & Destroy in Windows XP operating system. The paid sofware in this case is Norton Internet Security 2009 in Windows Vista operating system.

You can protect your pc against different security threats prowling on the cyberspace by using free tools. The protection these programs offer is quite good. You may wonder why an earth to use so many spyware scanners? The answer to this question is simple. One scanner was not able to detect all threats, so it was appropriate to use several. All these spyware and virus detection and removal tools worked well and did their mission. Spyware Doctor is worth to mention, because it was the only program to detect register files infection. This phenomena reduced the performance of my computer remarkably, if it appeared.

When I bought a new computer, I decided to purchase Norton Internet Security 2009. The brand name was familiar to me previously, because as a Yahoo mail user I happened to know that Yahoo scans all attachments by using Norton Antivirus. So I thought it was a good choice. I have now used  Norton Internet Security 2008 and 2009 over one year. I was able to upgrade to the new version for free. After I started to use the 2009 version, I noticed that it was more user friendly and faster than the 2008 version. Many times when I used the older version I wondered, why I have to do so many clicks in order to get my database updated. Now in this version of 2009 updating is easy and automatic as well as scanning.

The free tools I used before detected several times all kinds of spyware, adware and viruses on my computer. It seemed that there were certain “security holes” in this system through which malware was able to access into the computer. In addition, it took time to scan the computer by using several different scanners. Norton Internet Security 2009 provides more comprehensive protection against all kinds of security threats. It has antivirus, spyware protection, two-way firewall, intrusion prevention, operating system and application protection as well as web site authentication. Based on my experience, I can say that Norton Internet Security 2009 has provided a very good protection and it has kept my computer clean. It has not even detected any serious infections.