I’m a user of windows xp. I installed comodo firewall pro about three months ago on a fresh copy of windows xp. I did not install an antivirus at the time. I just installed one today, and the results of the first virus scan were 7 harmless browser cookies. For a free software firewall, this one rules. This thing is rock solid after just a bit of simple configuration. Great product, comodo. (:CLP)
Comodo also protects aganist viruses but in HIPS & Prevention Method. About 60& of unknown malware is blocked by CFP 3! (That was from a report when CFP 3 when final), This truly is great 
Josh