There is a wide range of antivirus softwares available: McAfee, Norton, Panda, and a whole lot others. The one which comes as a bundle in “system mechanic” (www.iolo.com) is pretty good. You can have its free trial (all functions enabled and very easy interface to work with) for 30 days. Please remember that a lot depends on how much time you spend on the internet. More usage will require that you also keep your antivirus very regularly updated (almost 500 or more viruses are added a month: McAfee.com information). Also a good way is to install the basic (free) version of Zone Alarm. It will protect you from ‘attackers’ when you are online. For spyware, I have found that “yahoo” spyware ( a new addition to the ‘my yahoo’ bar) is a good option to keep the hackers and attackers away.
If you choose any of the antivirus, and update it regularly you are only minimizing the chances of having your computer infected. None is 100% fool proof. Please keep that in mind.
Bon antivirus software.
My personal reccomendation: McAfee Shield and Antivirus or AVG (free or Professional editions).
There seems to be confusion between a firewall and a regular antivirus program. Lately almost all the antivirus softwares do have an integrated Firewall (against the attackers to your computer from the cyber highway). Zonealarm (free version) is basically a firewall to protect against the attacks to computers. True, Avast is a good free antivirus software.