Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
Click the the start button and press and hold down the shift key on the left hand side, while holding it down click on power and select restart. Now you can release the shift key and let the computer reboot.
you will see recovery option select recover select recovery options and check the option to roll back to previoius window click to select and it will revert to old windows os.
let me know if you need secure remote assistance.