windows defender should have an uninstaller listed in add/remove programs. Windows firewall cannot be removed, only completely disabled.To disable it, go to security center and set it to 'off' then go to control panel -> administrative tools -> services. Scroll down till you find a service called 'internet connection sharing/internet connection firewall' or 'Windows firewall/internet connection sharing (ICS). **WARNING** STOP HERE IF YOU USE INTERNET CONNECTION SHARING ** WARNING **. Open the properties of the service, click 'stop' and change the startup type to 'disabled'. Apply and quit the services manager.