One thing to consider with Windows 8+ is to disable the fast boot function in Power Options since when that is on Windows does not do a classic shutdown but goes into a hybrid state with stuff saved to disk and so speeds up booting up.
But it does mean that stuff is carried over from one On to the next On state.
I'm seeing this in an odd way on my multiboot computer with Windows 7 and 8.1 on it. If I Restart from 8.1 to 7 I can't go on line unless I ping using a non Windows application and on some occasions I will get my desktop background breaking up into tile like rectangles when switching from one user to another.
Disabling the Fast Boot function in Power Options has largely fixed this and I don't normally hang around waiting after I press the ON power button .....