Hi!
It is indeed a software issue, you just need to install Windows from scratch (your licence will be carried over automatically, con't worry too much about that).
You will need another laptop and a USB thumb-drive or DVD for this. Also, this will wipe all the data from the PC you are trying to fix.
First, have a look at this [https://www.microsoft.com/en-us/software-download/windows10|link] from Microsoft, this is where you'll get the Windows 10 Media Creation tool that will let you make the thumb-drive bootable (the section you need is the second one). Follow the steps outlined there. The open the section that describes how to install the new copy of Windows.
If you need more info (or advanced steps), have a look at this [https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/install-windows-from-a-usb-flash-drive|link], also from Microsoft.