It has come to my attention people are tricked into buying anti-virus software especially when buying from a walk-in retail store. It's bad because they overcharge for the software's true value, overcharge for the installation and the paid service often expires usually after a year. This can become problematic as sometimes the user is not aware they are no longer being protected and soon the computer becomes infected! It turns out there is good anti-virus software that is completely free! On my list for computer protection, I use: Avast Anti-Virus
Ad-Aware Pro ( got it for free from slickdeals.net)
All of these programs work together in harmony. Of course, I encourage safety Internet surfing! Don't be fooled anymore but if you feel you need a paid version, try and find a discounted price on it! Some paid software is sometimes free (like Ad-aware) or really cheap after some discount such as a mail-in rebate.