Private Sub cmdOpenExcel_Click()
Dim xlApp As Excel.Application
Dim xlWB As Excel.Workbook
Set xlApp = New Excel.Application
With xlApp
.Visible = True
Set xlWB = .Workbooks.Open("C:\path\xlfilename.xls", , False)
End With
'Add the textbox values to the cells in the workbook
...
'Save and Close
xlWB.Save
xlWB.Close
Set xlWB = Nothing
Set xlApp = Nothing
End Sub