w10 uses a hibernation file for it's "fast boot" and if that's messed up a bit, it probably DOES keep restarting. See if a true shutdown and start of a new "fast boot" file helps.
I checked a different threat, and it seems older and not fully my problem. Windows 10 updated a few days ago I believe. And the past 2 days I've gone to turn off my computer - what happens is it goes through all the motions of shutting off. But the computer won't fully turn off its still got the lights and fans running... I wait about 15 seconds and my computer starts turning back on again as if I had tried doing a restart instead. The only way to fully turn it off is to hit and hold down the power button for a few seconds. (I make sure to shut all programs down and don't get any errors when I hop back on).
I've noticed something but it might be unrelated, the internet suddenly decides to stop working and this seems to be when the problem occurs. Restarts fix the internet, but the ability to properly shut my computer down remains a proble,.