Enter Safe Mode using Windows 10 Install USB and Command Prompt

1. Boot USB and set  language
2. Select Repair your computer
3. Select Troubleshoot > Command Prompt
4. Use Bcdedit to set Safe Mode on boot as follows

bcdedit /set {default} safeboot minimal

5. Close Command prompt
6. Select Turn off PC
7. Power up PC to enter Safe Mode

To stop PC entering Safe Mode on every boot run System Configuration tool (msconfig) and under Boot options untick Safe boot, click OK and close