Thats what he was wanting to be fair, a complete clean install, basically to clean all rubbish out and make it run smoothly.
Not sure why he first attempted a "factory reset" rather than a clean install of Win 10.
Clean install is easy enough. Standard method is making a USB flash drive installer via Microsoft's "Media Creation Tool", using a flash drive of at least 8 GB in size.
Boot from it. Delete ALL partitions when offered the choice, leaving all of the drive empty "unallocated space". Let the installer make the necessary partitions as needed while the PC reboots a time or two.
But you are dead in the water for 12 hours now.
Not sure what is best procedure given that, but you may have to simply shut down and see where that leaves you.
Maybe others will comment.
What are his basic specs? CPU, SSD, RAM, video card?