Thanks for the tip.  In the System Log, on boot, I'm getting 4 disk errors.  Except for a forced power off error (from a failed chipset driver update) there are no other errors.  All 4 are:
"The driver detected a controller error on \Device\Harddisk1\DR1"
The 4 errors happen one after the other.
My first build was on a new SSD.  My second fresh build was using a new, typical SATA3 drive.  New bad hard drives are rare.  Two in a row would be very unlikely.  I have another and don't mind trying, but I think the problem is elsewhere.
In case I'm looking at the wrong place, is there a way to see what process is taking so long?  I don't see where the time to load is shown for each item.  I tried adding Processor, Kernal, and User Times to the columns, but they're all blank.
Thanks in advance for any insight.