Schvenn.net

This is another aftermarket free firewall, but this one seems to have a growing following because even the free version automatically includes anti-virus protection. You can download the firewall and anti-virus as separate components or together as one, integrated package.

I'm not overly familiar with this firewall, but it's free and I've seen a few reviews that rate it fairly well. I'm including it because you should keep your options open.

I don't use after-market software firewalls, because I use a router along with the Windows firewall. However, there are several very good, free firewall solutions of which, this is one.

This program is an add-on to the existing Windows firewalls that gives you added control to both inbound and outbound traffic.

This is a firewall that's been around for a long time and has some very die hard fans. It is very effective. It was my favourite software firewall before I purchased my first router.