codice:
Option Explicit
Dim xlApp(1 To 2) As Excel.Application
Dim xlWkB As Excel.Workbook
Dim LastCellSorgente As String
Dim LastCellDest As String
Dim RIGA As String
Dim a

Private Sub cmdAccoda_Click()
If txtFileSorgente = "" Then
    MsgBox "Indicare il file sorgente", vbExclamation, Me.Caption
    txtFileSorgente.SetFocus
    Exit Sub
End If
If txtFileDestinazione = "" Then
    MsgBox "Indicare il file di destinazione", vbExclamation, Me.Caption
    txtFileDestinazione.SetFocus
    Exit Sub
End If
Me.MousePointer = 11
'File Sorgente
Set xlApp(1) = New Excel.Application
xlApp(1).DisplayAlerts = False
'File Destinazione
Set xlApp(2) = New Excel.Application
Set xlWkB = xlApp(2).Workbooks.Open(txtFileDestinazione)
xlApp(1).Workbooks.Open (txtFileSorgente)
LastCellSorgente = xlApp(1).ActiveCell.SpecialCells(xlCellTypeLastCell).Address
LastCellSorgente = Replace(LastCellSorgente, "$", "")
LastCellDest = xlApp(2).ActiveCell.SpecialCells(xlCellTypeLastCell).Address
RIGA = Mid(LastCellDest, (InStrRev(LastCellDest, "$") + 1))
xlApp(1).Range("A1:" & LastCellSorgente).Copy
If RIGA = 1 Then
    xlApp(2).Range("A" & RIGA).PasteSpecial xlPasteValues
Else
    xlApp(2).Range("A" & (RIGA + 1)).PasteSpecial xlPasteValues
End If
xlApp(1).Quit
xlApp(2).Range("A1").Activate
xlWkB.Close (True)
xlApp(2).Quit
Set xlApp(1) = Nothing
Set xlApp(2) = Nothing
Me.MousePointer = 0
MsgBox "Operazione terminata", , Me.Caption
End Sub

Private Sub cmdEsci_Click()
End
End Sub

Private Sub cmdFileSorgente_Click()
cdApriFile.ShowOpen
txtFileSorgente = cdApriFile.FileName
End Sub

Private Sub Command1_Click()
cdApriFile.ShowOpen
txtFileDestinazione = cdApriFile.FileName
End Sub