An error occurred while attempting to start the selected virtual machine(s).
New Virtual Machine (in quotes) could not initialize.
The virtual machine could not be started because the hypervisor is not running.
New Virtual Machine (in quotes) could not initialize.  (Virtual machine ID blah-blah-blah)
The virtual machine could not be started because the hypervisor is not running.
The following actions may help you resolve the problem:

1) Verify that the processor of the physical computer has a supported version of hardware-assisted virtualization.

2) Verify that hardware-assisted virtualization and hardware-assisted data execution protection are enabled
   in the BIOS of the physical computer.

   (If you edit the BIOS to enable either setting, you must turn off the power to the physical computer and then turn it back on.
   Resetting the physical computer is not sufficient.)

3) If you have made changes to the Boot Configuration Data store, review these changes to ensure
   that the hypervisor is configured to launch automatically.

 

In my case I had no way of knowing whether my expensive server contains hardware for hardware-assisted virtualization (supported version or NOT).  It isn't printed on the system unit case.  It isn't reported by any of Microsoft's tools.

 

It turns out there is a BIOS setting that is DISABLED by default.  That means I must ENABLE it to run Hyper-V.  Presumably those computers that have it enabled take a performance hit.   But you won't find information on that.  

 

The phrase "the hypervisor is not running" refers to what?   A hypervisor is an operating system that hosts operating systems.  If it isn't running, what do I gotta to do get it running?  And what do I care if it is running or not?   That's a problem for Hyper-V to deal with.  

 

There is a note about BOOT.INI, which has transmogrified without notice into the Bootstrap Configuration Data store.  Apparently Hyper-V is dependent on one or more (we don't know which) settings inside the aforementioned store that is (are) responsible to launch the hypervisor automatically.

 

In an ideal world, this aside from Hyper-V would include by reference documentation that is specifically written to help people who are new to Hyper-V to use Hyper-V.  Alas, there is no such reference.  Pity.