As long as your Windows local firewall is enabled, port 80 *inbound* is always blocked. For port 80 *outbound*, this is always open by default and blocking it will mean virtually all websites will be unreachable.
To my knowledge, the Windows firewall doesn't support the blocking of outbound ports, only inbound ports. It’s just a basic firewall w/ not many other features/options. You’ll probably have to consider something from the many available third party firewalls.