windows failed to start error 0xc0000225

hi, 

my lenovo yoga 2 11 was working fine yesterday.suddenly it  turned off .when i tried to boot it up. it shows windows failed to start..

on booting again it shows 

'windows boot manager boot failed'.

after this it stucked at  loading files for hours .so i tried to recover windows with bootable usb. but its not detecting usb .

I looked up on internet all solution were directing to change boot mode from uefi to legacy but here its greyed out .

Again after looking up on internet i tried to disable secure boot, secure boot shows disabled but serure boot status shows enabled(blacked)

i've even set master password to see if it changes but no

I cant figure out what is wrong here how can i boot up windows pls help.

sorry for my bad english