Private Sub lvwZeit_Click()
Dim i As Integer
Dim j As Integer
For i = 1 To lvwZeit.ListItems.Count
If lvwZeit.ListItems(i).Checked Then
 For j = 0 To lvwZeit.ListItems.Count
      If i <> j Then
        lvwZeit.ListItems(j).Checked = 0
      End If
    Next j
End If
Next i
End Sub