I bought Dell Latitude E6400. On two occasions the start button would not turn on. I had to disconnect the computer, wait a few hours and then reconnect. It was an unpleasant experience. I sent a letter to USA Notebooks, Inc. saying that I would like to return my computer to the company and asking for instructions how to do it. . A gentleman called from the :USA Notebook I explained the situation. He promised to send an email with instructions. I am still waiting.