IsScreenSaverRunning

Option Explicit
Private Const SPI_SCREENSAVERRUNNING = 97
Private Declare Function SystemParametersInfoSS _
Lib "user32" Alias "SystemParametersInfoA" _
(ByVal uAction As Long, ByVal uParam As Long, _
ByRef lpvParam As Any, ByVal fuWinIni As Long) As Long
Private Sub Timer1_Timer()
If SSRunning Then Beep
End Sub

Private Function SSRunning() As Boolean
Dim lRetVal As Long
Dim lRunning As Long
On Error Resume Next
lRetVal = SystemParametersInfoSS(SPI_SCREENSAVERRUNNING, 0&, lRunning,0&)
lRetVal = SystemParametersInfoSS(SPI_SCREENSAVERRUNNING, lRunning, 0&,0&)
If lRunning <> 0 Then
SSRunning = True
End If
End Function