请老师看一下，VB不能实现重启，关机！ 老师

wpj0623

声明部分
Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long
代码部分
Private Sub Command1_Click()
    ExitWindowsEx EWX_LOGOFF, 0
   
End Sub

Private Sub Command2_Click()
    ExitWindowsEx EWX_REBOOT, 0
   
End Sub

Private Sub Command3_Click()
    ExitWindowsEx EWX_SHUTDOWN, 0
End Sub

XP系统，单击这三个按钮的效果是一样的，三个按钮都只能注销，而不能重启，关机，请问老师这是怎么回事？