Einzelne werte aus Tabellenblättern in Mappen

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Address = "$A$1" Then
Sub WerteInA1Zusammenfassen()
Dim wbs As Worksheet, strInput As String, i As Integer
Set wbs = ThisWorkbook.Sheets(1)
wbs.Range("B23") = ""
strInput = "C:\Quartal 1"
Application.ScreenUpdating = False
Application.EnableEvents = False
On Error Resume Next
With Application.FileSearch
.LookIn = strInput
.FileType = msoFileTypeExcelWorkbooks
.Execute
For i = 1 To .FoundFiles.Count
Workbooks.Open .FoundFiles(i), False
wbs.Range("B23").Value = wbs.Range("B23").Value + ActiveWorkbook.Sheets(1).Range("B23").Value
ActiveWorkbook.Close savechanges:=False
Next
End With
Application.EnableEvents = True
Application.ScreenUpdating = True
End If
End Sub