Fix CISCO VPN service has not been started

Sometimes CISCO VPN client will conflict with other services. In my case, it will popup a dialog said: "CISCO VPN service has not been started".
Check windows services, you can see CISCO VPN service is stopped. Even try to start it, but it turn to stopped immediately.
After research from Google, it's Internet Connection Sharing (ICS).
Please refer to http://www.lamnk.com/blog/vpn/error-56-the-cisco-systems-inc-vpn-service-has-not-been-started/

Just manually stop Internet Connection Sharing, then turn on CISCO VPN service. Everything is fine now!!