Network Address Translation (NAT) cannot start because Windows Firewall is turned on, or because a connection has been shared ...

Network Address Translation (NAT) cannot start because Windows Firewall is turned on, or because a connection has been shared with Internet Connection Sharing (ICS).
Click Start, click Administrative Tools, click Services, search for the Windows Firewall(WF)/Internet Connection Sharing (ICS) service. Make sure the service is both stopped and disabled before you add NAT.