I decided to install linux ,dualbooted, on my laptop but ran in some issues . I installed several corrupt installs causing me to allocate most of my harddrive ,at least the parts that do not contain my windows partition.Now to get rid of it I used kali on usb which worked well. On wanting to shutdown my system i accidently pressed the logout screen.Which gives me an authentication screen to get back in ,authentication that i did not create since i am running a usb persistence option for kali.And i cant shutdown the system because i get a system policy prevents stopping the system when other users are logged in.I tried just turning the power of ,but when it boots back up ,it immediatley goes back to the auth. screen of kali so i cant access my bios.I also removed usb, to no avail...How can i get out of this mess i got myself into and just boot windows again? 
How can i get out of the authentication screen and shutdown?
system installation;kali linux;authentication
toor was a valid password for root, so i was able to shutdown. Problem solved