Dim filepath As String = "ля-ля-ля..."            
          
            Dim buffer( 10000 ) As Byte

            ' Length of the file:
            Dim length As Integer

            ' Total bytes to read:
            Dim dataToRead As Long

            ' Identify the file name.
            Dim filename As String = System.IO.Path.GetFileName(filepath)

            Try
                ' Open the file.
                iStream = New System.IO.FileStream(filepath, System.IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.Read)

                ' Total bytes to read:
                dataToRead = iStream.Length

                Response.ContentType = "application/octet-stream"
                Response.AddHeader("Content-Disposition", "attachment; filename=" & filename)

                ' Read the bytes.
                While dataToRead >  0 
                    ' Verify that the client is connected.
                    If Response.IsClientConnected Then
                        ' Read the data in buffer
                        length = iStream.Read(buffer,  0 ,  10000 )

                        ' Write the data to the current output stream.
                        Response.OutputStream.Write(buffer, 0, length)

                        ' Flush the data to the HTML output.
                        Response.Flush()

                        ReDim buffer( 10000 ) ' Clear the buffer
                        dataToRead = dataToRead - length
                    Else
                        'prevent infinite loop if user disconnects
                        dataToRead = - 1 
                    End If
                End While

            Catch ex As Exception
                ' Trap the error, if any.
                'Response.Write("Error : " & ex.Message)
            Finally
                If IsNothing(iStream) = False Then
                    ' Close the file.
                    iStream.Close()
                End If
                Response.End()
            End Try

<configuration>
   <system.web>
      <httpRuntime maxRequestLength="4000"
         useFullyQualifiedRedirectUrl="true"
         executionTimeout="45"
         versionHeader=""/>
   </system.web>
</configuration>