There is very well known security flaw in microsoft windows. That you simle boot a linux OS from flash drive e.g Kali Linux. And just replace a cmd file with sethc file and you can prompt cmd with administrator rights on lock screen of windows by pressing shift key 5-6 times. And then you can easily update passwords of currents users and so on.
Now I have tested this on windows XP, Vista, Windows 7, Windows 8 and Windows 8.1. I have not tested it on windows 10 yet.
So why does microsoft leave this flaw ? Or is there any chance that they do not know about this ?