'API調(diào)用與常用定義：
Private Declare Function SystemParametersInfo _
  Lib "user32" _
  Alias "SystemParametersInfoA" _
   (ByVal uiAction As Long, _
    ByVal uiParam As Long, _
    pvParam As Any, _
    ByVal fWInIni As Long) As Boolean
 
Private Const SPI_GETSCREENSAVEACTIVE As Long = &H10  '屏保是否啟用的常量
Private Const SPI_GETSCREENSAVERRUNNING As Long = &H72 '屏保是否運(yùn)行的常量

Private Sub Timer1_Timer()
  Dim bRunning As Boolean   '屏保是否運(yùn)行的變量,當(dāng)然你可以定義全局變量
  SystemParametersInfo SPI_GETSCREENSAVERRUNNING, 0, bRunning, False '調(diào)用API,bRunning返回屏保運(yùn)行狀態(tài)
  Debug.Print Time; "屏保運(yùn)行="; bRunning '演示:打印屏保是否運(yùn)行的信息
End Sub
 
'另外,查看屏保是否啟用,也可以用下面方法:
SystemParametersInfo SPI_GETSCREENSAVEACTIVE, 0, bActive, False 'bActive為返回值(邏輯型)

Option Explicit
Private Declare Function GetLastInputInfo Lib "user32" (plii As LASTINPUTINFO) As Boolean
Private Declare Function GetTickCount Lib "kernel32" () As Long
Private Type LASTINPUTINFO
  cbSize As Long
  dwTime As Long
End Type
 
Private Sub Form_Load()
   Timer1.Interval = 1000  
End Sub
 
Private Sub Timer1_Timer()
  Dim lii As LASTINPUTINFO
  lii.cbSize = Len(lii)
  If GetLastInputInfo(lii) Then
    If (GetTickCount - lii.dwTime) / 60000 >= 15 Then      
      Call MsgBox("由于本機(jī)15分鐘沒有操作，如果3分鐘后沒有反應(yīng)，系統(tǒng)將強(qiáng)制關(guān)機(jī)", vbYesNo + vbExclamation + vbDefaultButton2, "提示")
    End If
  End If
End Sub