I don't recommend Zone Alarm products anymore. They've had too many bugs w/ Windows 7. My best recommendation for a firewall would be Comodo. Anti-Virus is another story, either Avast or Microsoft Security essentials probably.
Check the results of AV-Comparitives tests for the best anti-virus http://www.av-comparatives.org/
You'll also need a spyware/malware scanner. I recommend SuperAntiSpyware and/or Malwarebytes' Anti-Malware.