When installing Apps make sure you install using admin rights, especially when running steam, or when installing apps on steam make sure you have admin rights, or some of the visual basic packages might not install properly.
If your modifying hardware, do not forget to disable DSE. Also, I think there are issues with some types of Optimus working, so you might want to stick to dedicated modes for your main GPU.
As for DX12, forget it, its not really being used yet, for the witcher 3 fans you will want 352.85 or 353.17 or later drivers but I wouldn't recommend going further. (nVidia of course)
You can disable Cortana.
You should know that to change some major settings you will have to go to "recovery" and advanced - like you did in windows 8 to change settings.
Also, for people with MEI on a intel chipset (like z97 etc..), you might need to update to the latest firware or maybe you will have sound issues or other on-board hardware issues.
If you want to bring back some menu's to startup, like you had in windows 7 do this :
open up a command prompt / type CMD into the search field, and run the command prompt with admin
type "bcdedit /set {default} bootmenupolicy legacy"
Reboot, you should now have that option..like hitting F7 to disable DSE or like F3 or whatever for safemode with networking etc..
for those of you who have a UEFI version of windows 10 on a USb disk and it does not see your harddrives when your trying to install via USB etc..
you can format your drives to the right type ( i.e GPT partition..instead of legacy's old MBR system)
when windows is at the setup screen (you know before you even selected to "INSTALL Windows")
Hit "F10 + Shift"
this should allow you to bring up a command prompt.
from there do the following :
diskpart
(it will ask to select the disk)
diskpart > list disk
diskpart>select disk x
diskpart>clean
diskpart>convert>
EXIT
Install windows now and you should see the harddrive, this erases all mixed partitions on it, fixes errors and gets rid of the pesky hard to get rid of MBR file system that you may have been using since XP days...
these are common issues Ive seen people needing to know, if there are any other issues I can help with, maybe Ive run into them a hundred dozen times and know a fix. if not, google is always your friend.
hope this stuff helps.