1
Are you able to boot into the Recovery Environment using these steps to access Command Prompt?
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 - Command Prompt.
2
If you are unable to access the Recovery Environment using those steps, then you will need to create a bootable Windows 10 USB on an empty 8GB USB flash drive on another working PC and boot your PC from that, then rather than installing Windows 10, select ‘Repair this Computer’ that will give you access to the Recovery Environment from there
In the Recovery Environment on the USB, try each available recovery option.
Click this link: https://www.microsoft.com/software-download/windows10
to download the Media Creation Tool (Click on Download Tool Now), with that you can create a bootable USB flash drive (min 8GB) using that tool
Then, Boot your PC from the Installation Media you just created.