I changed permissions to a folder in order to have access to delete the files. I was trying to update to the anniversary update but received an error which was why I needed to change permission to delete a temporary files folder. I am the admin. However once I restart the Surface I get either the surface logo and the swirling reboot icon (dots in circle) and it just sits there or I get just the circles and it sits. Is there a way I can boot into safe mode? I cannot get to my desktop screen.