What is Spotlight-V100 ..... It is not in El Capitan but is in macOS Sierra is it a valid file or what?

macOS Sierra 10.12.5 on a

17" MacBook Pro (circa Late 2011)

2.5GHz, 8GB 1333MHz DDR3 memory, 750GB HD,

Graphics - AMD Radeon HD 6770M 1024 MB, Intel HD Graphics 3000 512MB.

Reading news emails when the mouse curser just disappeared from view.

Gave the mouse a wiggle to try and locate that curser when suddenly the computer just shut down, restarted and shut down again,

This was a most unsettling behaviour, on a computer that had been extremely and dependently reliable, from the day it was purchased new.

However initial attempts to stabilise and return it to normal behaviour failed.

So using Recovery Drive (Latest Update) the reinstallation of the mac software was initiated.

All seemed to be well until I went to test run the back-up drive, the back was chosen and the computer went almost immediately in multiple shut down/and restart again.

Alas after doing a few tasks being put to sleep for the night the following day it repeated the problem.

The back-up drive was reloaded with the macOS through restore, initiated and put into the task of running the computer whilst the Micromat app TechTool Pro v9.5.1 was brought into action all was running smoothly until File Optimisation was selected when 'halfway' though that task the computer shut down restarted and continued with the task uninterrupted when given the tick to proceed.

From this exercise it was noted that three files just refused to be Optimised and they are directly related back to this Spotlight-V100 which is greyed out -though still active- this in turn shows two sub folders Store-V1 & Store-V2

there are 105 items in each folder. Store-V1 is barred with red dot with a white bar through it. Store-V2 is accessible but does not appear to react when clicked upon nor do any of the items listed.
The question is this File Spotlight-V100 is not in the initial directory for El Capitan running on my Mac Pro early 2009

2 x 2.26GHz Quad Core; 8GB 1066Mhz DDR3; etc. and I am asking first what is it? and can it be deleted without any adverse effect upon the stability of the MacBook Pro main operating system.

Anyone 'out there' that can help, explain or give a guide as to what is what, and what can be done would be greatly appreciated.

The summary below indicates Mac Pro, OS X Mountain Lion, the Doc working okay on MacBook Pro ---how wrong can things get??