The Windows update will try to installer a driver over a newer one. Aparently it's Nvidias fault. Doesn't take much to fix though.
When you update you get the option like you did with 8 over 7 of doing a fresh install with nothing kept. It dumps everyone in windows.old folder. I usually do this but I recently reinstalled anyway I did the "keep all the stuff" option and it worked really well. Ran the system files cleaner afterwards and the old windows version is dead, since I don't need to revert.
Upgraded 4 PCs with Windows 10 now and had no issues at all. Works perfectly. I was slightly worried when doing it to my new Dell XPS laptop but it turned out without a problem. Even my CH HOTAS works and the drivers are not signed for 10. Two of the machines I upgraded were 7>8>8.1>10 upgrades in series so if something could go wrong it would have been with those.
The only confusion I had over the whole thing was the Nvidia problem and my mobo driver for the Intel onboard GFX chip which I used for a third screen. The driver didn't install, so disabled the device, removed the driver, enabled and then windows update sorted out the new version.