System seemed good at first but, after 6 months of light duty usage, the disk controller failed.  On startup, Windows 10 begins to run and allows login.  After a minute or two, the Dell system diagnostic suddenly pops up, makes all sorts of whistles and noises, and complains of absent hard drive.  If that were true, where did Windows 10 come from?No returns after 3 months so I get to write this one off to life experience ....