test

Sub RewriteData()
    Dim fp As String, fn As String
    Dim wb As Workbook, ws As Worksheet
    Dim lc As Long, c As Long, r As Long
    Dim v1#, v2#, v3#, v4#
    If MsgBox("TypeA? (No=TypeB)", vbYesNo) = vbYes Then
        v1 = 10: v2 = 10.11: v3 = 100: v4 = 10
    Else
        v1 = 20: v2 = 20: v3 = 20: v4 = 20
    End If
    With Application.FileDialog(msoFileDialogFolderPicker)
        If .Show <> -1 Then Exit Sub
        fp = .SelectedItems(1)
    End With
    Application.ScreenUpdating = False
    Application.DisplayAlerts = False
    fn = Dir(fp & "\*.csv")
    Do While fn <> ""
        Set wb = Workbooks.Open(fp & "\" & fn)
        Set ws = wb.Sheets(1)
        lc = ws.Cells(1, ws.Columns.Count).End(xlToLeft).Column
        For c = 2 To lc
            ws.Cells(3, c).Value = v1
            ws.Cells(4, c).Value = v2
            ws.Cells(5, c).Value = v3
            ws.Cells(6, c).Value = v4
            For r = 7 To 50
                ws.Cells(r, c).Value = 0
            Next r
        Next c
        wb.Close SaveChanges:=True
        fn = Dir()
    Loop
    Application.DisplayAlerts = True
    Application.ScreenUpdating = True
    MsgBox "Done"
End Sub