Start your System, then just after the Manufacturers logo disappears and Windows 10 tries to boot, press and hold the power button down for 5 - 10 seconds to perform a hard shut down
Do this Twice
On the third boot attempt, Windows will boot into the Windows 10 Repair Environment, from there you can access Startup Recovery, Safe Mode, Command Prompt . . . etc.
Go to Troubleshoot - Advanced Options - Command Prompt
Run Each of these commands, press return after each command:
BootRec /fixmbr
BootRec /FixBoot
BootRec /ScanOs
BootRec /RebuildBcd
Close Command Prompt and reboot your System to see if it boots . . .
If that does not work: go to Troubleshoot - Advanced Options - System Restore, see if you have a recent restore point you can revert to
If you do not have a recent restore point, go to Troubleshoot - Advanced Options - Startup Settings, click restart.
Upon restart press 4 to boot into Safe Mode, if you can get into Safe Mode, backup your data, reboot and see if your system boots normally
If all this fails go to Troubleshoot - Advanced Options - Reset this PC, choose to keep all your files and Apps
This will re-install Windows 10 whilst keeping your data and applications