I never use a firewall…is to helpful…if yes…which is the ideal simple light firewall compatible with Avast to start with…not too complicated like Comodo…don’t wanna headache trying to configure or to bother you smart members? 
Regards!
If you dont understand firewall’s it’s best to stick with the window’s one but there are two very light and free firewall’s that i have been impressed with, privatefirewall and online armour.
Yezinki, I feel the same way, and the truth of the matter is that a poorly configured firewall can be almost as dangerous as no firewall at all…you will have a false sense of security.
I just use the Windows one. The Vista one is better than the XP one; it’s a two way firewall, although difficult to configure, so default is best.
I find that Avast and the NoScript option in my browser (Firefox) works brilliantly to prevent malware.
Vista and Seven firewalls offer only inbound protection by default, if you want the outbound protection too, this is doable although indeed not user friendly at all.
Now just to give an example of a native both ways firewall that’s easy to use >>> Avast Internet Security 5 seems to offer one IIRC ;D with an out of the box configuration that doesn’t require any user intervention at all.
I am very grateful & thank all Avast members who contributed by their recommendations based on their practical, tried tested experiences.
Best Regards!
If you don’t want outband connections (like Block a program to download updates) stay with Windows Firewall or your router Firewall.