Disable Windows Firewall and turn off Security Center Alerts

To turn off the windows firewall on domain pc's through gpo open group policy editor and navigate to:

Computer Configuration-Admin Templates-Network Connections-Windows Firewall-Standard Profile and select Windows Firewall: Protect all network connections and set it to disabled, do this for the domain policy as well.

Second your will need to turn off security center to stop the balloon popups.
Computer Config-Admin Templates-Windows Components and select Security Center in the right pane. Select Disabled to turn off the security center.