Dim objExcel As Object

Private Function Launch_Excel() As Boolean
    On Error Resume Next
    Set objExcel = GetObject(, "Excel.Application") 'Получаем не абы что, а что надо
    If objExcel Is Nothing Then Set objExcel = CreateObject("Excel.Application") 'Если excel не запущен, запускаем
    If Not objExcel Is Nothing Then 
        Launch_Excel = True
        objExcel.Visible = True
    End If
End Function

    
Dim a( 24  To  28 ) As String
Dim b( 24  To  28 ) As String
Dim rec As String
Dim i, f As Integer
With objExcel.Workbooks.Open(CommonDialog1.FileName) 'в экселе может быть несколько книг
    For i =  24  To  28 
        a(i) = .Worksheets("Ñâîä ").Cells(i,  4 )
    Next i
    For i =  24  To  28 
        b(i) = .Worksheets("Ñâîä ").Cells(i,  5 )
    Next i
End With