where can i find a good free firewall
Oh ok. Maybe Comodo http://www.comodo.com/home/internet-security/firewall.php? It also includes quite a lot of other features, which you may or may not like. There's probably a lot of other good firewalls out there, but as I just use the Windows firewall, I don't know that much about them.
I'm not saying that you should necessarily go by cnet's ratings, but at least there's a list of firewalls at http://download.cnet.com/windows/firewall-software/.
I use ZoneAlarm, and I've had a pretty positive experience with it. Worth checking out:
http://www.zonealarm.com/security/en-us/zonealarm-pc-security-free-firewall.htm
Keep in mind, a firewall doesn't do what most people think it does (at least not on modern networks). If you are behind a router, the NAT will work as a full firewall by design and protect you from anything coming in over the internet. Modern software firewalls are really only for LAN defense, and possibly blocking applications on your machine. As long as you trust your network, it's not really necessary to worry about it.
starofale wrote: Though a software firewall is still useful when using an untrusted network. Also, NAT will cease to be helpful when ipv6 becomes the standard.
Ehhh, I dunno. I think NAT will be there for a while longer, simply out of old habits and the lack of desire for people to adapt to the new standard, even once Ipv6 is implemented.