可以.
以下是应用程序启动函数(Main):
 static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);            // 保证只能有一个进程运行.
            bool isRun = true;
            Process cp = Process.GetCurrentProcess();
            Process[] p = Process.GetProcesses();
            for (int i = 0; i < p.Length; i++)
            {
                if (p[i].ProcessName == cp.ProcessName)  
                {
                    isRun = false;
                }
            }
            
            // 如果找到说明正在运行
            if (isRun)
            {
                MessageBox.Show("程序已运行...", "XX系统"
                    ,  MessageBoxButtons.OK, MessageBoxIcon.Warning);
                Application.Exit();
            }
            else
            {
                Application.Run(new LoginForm());
            }
        }