An anti-virus, as the name suggests, is a computer program which fights the viruses (and wins, hopefully!). But cleaning up the mess a virus left in your computer is not as easy as causing trouble. Mainly, an anti-virus should be able to perform the following tasks:
• Search for computer viruses
• Identify a virus by its signature(or other criteria)
• Eliminate a virus (delete or at least isolate it)

Of course, things are a little bit more complicated than that, but this is the base line.
This raises the question: “What is so complicated in creating a good anti-virus? Why so many anti-virus solutions claim to assure the best possible protection, yet nobody can say with certainty that a specific program is the best?”

I though about it for a while, I red a lot, and now I think I have an answer: it’s all about mathematics!!! Every anti-virus solution is based on algorithms. Each algorithm has in background a mathematical support. The more complicated the algorithm is, the harder for the computer to process it. The more resources the processor uses with the anti-virus the less resource remains available for the usual task that the computer has to do.

That’s why there are so many companies out there producing anti-virus software, because there are so many different approaches when dealing with computer viruses. Some base their algorithms on efficiency. That means catching all the viruses or other vicious creatures inside your computer. Others care more about not killing the computer while saving its life, so to speak. It’s understandable, as a perfectly protected computer that can’t perform any task is for no use.

To conclude, it’s a thin red line between an efficient anti-virus and a dead-wasting solution. For us, the users it’s a hard choice to make, because we have access only to what the producer wants us to know about its product, he always underlines only the best features(through marketing) but never tells us about the flaws.Still, a weak anti-virus is better than no anti-virus!!!