Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
        If (DataGridView1.Rows(1).Cells(1).Selected) Then
            MessageBox.Show("")
        End If
    End Sub

Private Sub DataGridView1_CellClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellClick
  '
  If e.ColumnIndex = 0 AndAlso e.RowIndex = 0 Then
    ' User clicked Col0 and Row0
  End If
 
End Sub

  Dim oCell As DataGridViewCell
  For Each oCell In DataGridView1.SelectedCells
    If oCell.ColumnIndex = 0 AndAlso oCell.RowIndex = 0 Then
      ' User has selected Col0 and Row0
    End If
  Next