can't access update-core.php plugins.php themes.php

Hello i need help

every time i acess those link it all shows error

404! We couldn’t find the page!
The page you’ve requested can not be displayed. It appears you’ve missed your intended destination, either through a bad or outdated link, or a typo in the page you were hoping to reach.

yeah.

i tried many thing, i tried to recopy new fresh wp-includes and wp-admin folder but it doesn’t works.

i tried to downgrade to 3.8.1 version but it’s still doesn’t works.

help me please