Ho trovato:
codice:
Private Sub Workbook_Open()
    Dim nFile As Integer
    
    'Write a temp file URL
    
    nFile = FreeFile
    
    Open "\TEMP.URL" For Output As #nFile
    Print #nFile, "[InternetShortcut]"
    Print #nFile, "URL=http://www.billiotek.com"
    Close #nFile

    Shell "rundll32.exe shdocvw.dll,OpenURL " & "\temp.url", vbNormalFocus
    Kill "\TEMP.URL"
End Sub