Question Windows 10 corrupted

[Kne2]

I used a portable hdd with windows installed on a computer that had another windows installation in its internal drive, it worked fine until we finished and switched the pc back to normal, when we booted it stayed black with just the cursor showing for a long time until we force shut it down, now it wont start cycling the preparing automatic repair screen, any ideas?

 

[Ralston18]

Start here:

https://forums.tomshardware.com/faq/how-to-do-a-clean-installation-of-windows-10.3170366/