title: "Class not registered" error when working with excel and visual studio 2010
body: <p>Hello i'm trying to import data from an excel to visual basic variables, but im getting an strange error. I did add the reference to microsoft excel com library.</p>
  
  <pre><code>Imports Microsoft.Office.Interop.Excel
  
  Module Module1
  
  Sub Main()
      ExtraerCostos()
  End Sub
  
  Public Sub ExtraerCostos()
  
      Dim numero As String
      Dim aux As String
      Dim costos(20) As Double
      Dim cant As Integer  
  
      Dim excelApp As New Microsoft.Office.Interop.Excel.Application
      Dim workbook As New Microsoft.Office.Interop.Excel.Workbook ' The error points to this line 
      Dim sheet As New Microsoft.Office.Interop.Excel.Worksheet
  
      excelApp = CreateObject("Excel.Application")
      excelApp.Visible = True
      workbook = excelApp.Workbooks.Open("C:\workbook.xls")
      sheet = workbook.Worksheets("Factura Detallada")
  
       'Irrelevant code
      numero = "111111111"
      cant = 12
  
      While numero.Length = 9
          cant = cant + 1
      End While
  
      For i = 12 To cant
  
          numero = sheet.Cells(i, 1).text
          For j = 3 To 22
              aux = sheet.Cells(i, j).text
              If aux = "-" Then
                  costos(j - 2) = 0
              Else : costos(j - 2) = Convert.ToDouble(aux)
  
              End If
              Console.WriteLine(costos(j - 2))
          Next
  
  
      Next
  
  End Sub
  End Module
  </code></pre>
  
  <p>Retrieving the COM class factory for component with CLSID {00020819-0000-0000-C000-000000000046} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).</p>