Are you able to access the recovery environment using these steps.
Start your PC, just as Windows attempts to load (spinning dots), press and hold Power Button for 5 - 10 seconds to perform a Hard Shut Down
Do this twice
On the third start Windows will boot into the Recovery Environment and from there you can access System Repair, Safe Mode, Command Prompt... etc.
Go to Troubleshoot - Advanced Option - Startup Repair
See if Windows startup can repair itself