Question Win7 shutdown at starting up logo

Dec 18, 2019
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Started Mon, Wife's PC. The startup Logo gets going then the whole PC shuts down. Pause for 3-5 seconds then starts back up.. rinse and repeat.
Safe mode: works great at VGA. Looked to see it any app updates happened. Might be some Office 2016 activity as I see downloaded files but that is it.
Win7 repair disk, tries to work but restarts.
Win10 Upgrade by USB, tries to work but restarts.
Took out gaming video card, used MB video, no change.
Swapped memsticks, tried single and dual, it only has 8gigs, no change.
Disconnected BU HD, only running single SSD. no change
No system restore ;{
I't a Gigabyte MB i5 i built years ago but was my most reliable till...
Suggestions?