Then I think you will need to repair the system.
If you don't have Win 10 install media then you can create either a bootable USB or DVD after reading -
https://www.microsoft.com/en-gb/software-download/windows10When you've done that, remove the install media and shut the machine down.
Tap F12 as you switch on to change the boot order.
If using an USB then plug that in before switching on.
Use the cursor keys to select either USB or the DVD drive which could be listed as ODD (Optical Disk Drive).
If using a DVD, insert it and after selecting that option, press enter.
If using a DVD you will be prompted to press any key to boot from CD/DVD - do that.
You will then be presented with an inverse window with Windows Setup [EMS Enabled] highlighted - just press enter.
You do not get those when using an USB.
When the media has loaded, navigate to the Install screen and click on Repair your computer.
Click on Troubleshoot and select Command Prompt then enter these cmds -
bcdedit |find "osdevice"
For clarity that is a Pipe symbol before find and is the uppercase of \
Using your partition letter instead of the x I have exampled, enter -
dism /image:x:\ /cleanup-image /restorehealth
You can usually disregard what it says about the scratch directory and wait for it complete.
Follow that cmd with this one, again using your partition letter instead of the X I have exampled -
sfc /scannow /offbootdir=X:\ /offwindir=X:\Windows
Enter exit to close the cmd window, remove the install media and reboot to see if the problem is resolved.
