Guide Clifford's guide to computer security and maintenance.

Anti-Virus and Firewalls are 2 completely different things, but are often packaged together into a single software. Anti-Virus doesnt really do what it says in the "Anti", it doesnt prevent virus' or do anything to stop them, it simply removes them if it finds them, and thats a big if.

A firewall on the other hand prevents unwanted traffic connecting to your computer, though most people are behind a router (not to be confused with modem), which does a pretty good job of filtering traffic out anyway, but the firewall just adds that extra layer from inside the network, should you be connecting to public networks, internet cafes, etc.

If you can be bothered with the extremely strict security, warnings for every new program you install/use, the way the anti-virus is constantly scanning active files on your system and instantly quarantines them without asking, and will continue to do so, even if you restore the object, until you've setup an exception. Then comodo internet security (free - they dont advertise it well, but there is a free version), then do so. Its the best firewall for windows i've ever come across and far surpasses anything else i've seen.

Otherwise i would suggest ESET or MS Security Essentials.