I had the Windows old folder but rollbacking mentioned cannot rollback as files needed were deleted. Though I had performed upgrade keeping everything. I was thinking of rollback coz of Win 10 slow boot & slow system response for stuffs.
As rollback wasn't possible I decided to fresh install. And fresh install solved everything slowboot, slowdown, etc... Guess upgrading is a mess, fresh install is always good.
Now I am liking Win 10. My previous OS was Win 7 so Win 10 is completely new for me. its going to take time to know the stuffs. But I have already disabled quite many things under settings & other places, etc... There are quite many unneeded stuffs enabled by default.