You may have to boot from a Windows 10 installation USB flash drive and repair your Windows installation.
You could create a Windows 10 installation by downloading and running the media creation tool from Microsoft website.
Make sure to have a flash drive of at least 8GB capacity.
Select "Create installation media for another PC"
Select Language, Edition and Architecture that matches that of your PC.
Select USB flash drive and after clicking Next, it will download and created the Windows 10 installation media.
Boot from the Windows 10 installation media and click Next on the first window.
On the next window select Repair your computer.
Select Troubleshooting>Startup repair>
If that fails,
Select Troubleshooting>System Restore>, select a restore point before the issue started.