安全关闭windows系统。关闭windows系统可以使用ExitWindowsEx这个API，但是有时关闭时有些进程会没相应，需要人为终止。所以在本程序中我先将用户进程先终止掉，然后再关闭系统。-closed windows security system. Close windows system ExitWindowsEx can use this API, However, sometimes when some of the closure process will be no corresponding need for artificial termination. So in the process I first users swap termination process first, and then the system down.