有天突然發現 notebook 上的 VPN connections set up 不見了，google 後發現有一些人有相同的問題 http://forums.techarena.in/windows-vista-network/706291.htm，沒人提供解決方法，找了好多資料，測試 OK！
control panel => system manage tools => services => start "Telephony" service,
(控制台=>系統管理工具 =>服務 =>啟動 "Telephony" 服務)
大概我在整理系統時(跑太慢)關掉了。
In my case, VPN set up connection cannot be saved. After start service "Telephony", VPN connections appear!
It may be caused by VPN connection needs a telephone related service(VPN has a dial-up selection!).
