The simplest solution is to do a new installation of LibreELEC over the current setup. But... I don't know if you have any data currently on your nettop that needs to be saved first.Another more complex solution is to use a bootable USB stick/SD card that runs Ubuntu or another Linux Live session. Then the correct system files can be copied manually to LibreELEC's system partition.
Thanks for the info i have no importance files that needs to be saved. Ill do the 1st method