C#寫的關機程序，代碼簡單主要是用Process類來操作，當然也可以調用

                                系統API來執行操作。                                       

                                主要代碼為：

                                關機

                                Process.Start("shutdown", "-s -t 0");

                                注銷

                                Process.Start("shutdown", "-l ");

                                重啟

                                Process.Start("shutdown", "-r -t 0");

                                更多的關于Process類的操作，可以了解

                     http://msdn.microsoft.com/zh-cn/library/system.diagnostics.process_members(VS.80).aspx