avast isn’t a firewall so you will need a third party firewall, although the Network Shield provides very limited protection to common attack ports. If you are using XP SP2 there is also the windows firewall although that provides no outbound protection.

When you mention ‘New Work Laptop’ in your topic title, if this is to be used for work purposes at home you wouldn’t qualify for the free home version (home, non-commercial use) you would need avast pro.