firewall and antivirus are mandatory

Firewall is a device or software which permit, deny, encrypt, or proxy all the information passing through it based on rules configured in to it.

Firewalls are systems designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both Hardware and Software, or a combination of both.There are so many firewalls which offer stateful packet inspection, deep packet inspection, applicaton layer firewalls,proxy firewalls.

Windows has a built firewall for xp but it offers only inbound protection. A firewall should be able to stop the internal processes from outbound communication also so that if a virus attack happens any outbound intenet communication is denied by default.

Topmost personal firewalls include Zone Alarm, Kaspersky Internet Security Suite which offers complete protection with web antivirus,firewall,file antivirus etc. Comodo firewall also offers a good protection on outbound communication. Even if you have a firewall if you did not configure it properly it will result in poor security.

You should configure in such a way that only necessary programs should be able to communicate and deny all other programs. Comodo offers a parental control feature to control the alerts that you will recieve from the firewall if you put a password there is an option to suppress the firewall alerts and defense alerts. if you use comodo you should install a antivirus solution also.

Bitdefender is also an internet security suite offering the same protection as kaspersky and also tops the 2008 antivirus reviews.

In kaspersky you should configure the firewall in high security mode so it will not show any alerts and denies the outbound communication if that program is not configured to use internet by default.

Also see scan for missing patches