What is antivirus software?
There are a variety of antivirus software packages that are active in many different ways, depending on how the vendor chose to implement their software. What they have in common is that they all look for patterns in files or memory of your computer that the possible presence of a virus in te geven. Antivirus packages know what to look through the use of virus profiles (sometimes called "signatures") provided by the seller.

New viruses are discovered daily. The effectiveness of antivirus software is dependent on the latest virus profiles installed on your computer so they can look for recently discovered viruses. It is important to these profiles up to date.