Should I invest in a Anti virus programme and how do they work?

You'll never regret investing in a good anti-virus utility for your system. It's like insurance—even if you never accidentally download an infected file, you'll be extremely glad you have the program when it protects you. For instance, one friend saved himself from having to reinstall his entire system because his copy of McAfee's VirusScan identified a virus in a file a commercial artist had given him. Surprisingly, the artist knew his computer had been crashing a lot lately, but still couldn't be bothered to get an anti-virus utility for himself—he's probably still passing out infected files to his clients.Unfortunately choosing a anti virus programme is not as simple as it should be.Some programmes, even well know brands can actually slow your computer down so much as to stop its effecient functioning.

Always make sure you only have one AV programme installed on your pc at one time as having two or more working simulataneously can really effect a pc's performance not to mention affect the efficacy of its AV programme.

Anti-virus Programs

The most popular anti-virus programs—whether they're free, like Disinfectant for the Mac, or cost about $40, like VirusScan for Windows, will scan your hard drive for infected files. They look for markers, usually internal strings of code, for known viruses, and sometimes also check a file's name against a database of known trojan horses. The commercial programs also often let you update their database of known viruses and trojan horses, either for free or for a nominal fee. But since this won't catch the newest of the new viruses, the programs can also check to see if a program, or your system, is modifying itself. But though this is a good indicator of a virus, it can also mean you've added a utility to your system, or you're using a self-modifying program, like a database, and the many false-positives you get can be annoying. If they've identified a virus in a file, the programs can also strip the virus out of the file, but I don't recommend doing so. If you're a conscientious computer user, you back up your computer regularly—that is, every time you use it. It's best to replace an infected file with an uninfected copy. Though an anti-virus program will successfully remove a virus (or tell you if it can't), it could damage the original file, or worse yet, leave a "virus ghost" that sets off the anti-virus utility's alarm, even though it's harmless.

The very best programs can also scan a floppy disk when you insert it into your floppy disk drive, and check a downloaded file the moment it's complete on your drive—or alternately, quickly check a file when you launch it—so you're protected before a virus can even make it to your system.

The latest trend in malaware is what is called "drive by downloads" which inserts malicious coded iframes from seemingly innocent websites.This exploit takes place automatically and undetected by website surfers.Google the well known search engine has "found more than three million unique URLs on over 180,000 web sites ".

The Internet is a fabulous resource. You can download hard-to-find files and programs at any hour, day or night, onto your computer system. You don't have to isolate yourself to protect yourself, but you should have some insurance against the nasty, invisible viruses and trojan horses that can bring your computer to its knees.