(By the way, you have backed up your computer, right?) In both cases, I was able to save an otherwise unusable PC by doing a reset, which removes all (or most) of the files and apps on the hard drive and reinstalls Windows 10. I was reminded of this just the other day, when another Windows 10 system decided that it didn’t like the latest update and began misbehaving very badly - so badly, that it would stop reacting to the cursor one minute after it booted. The battery ran out in the middle of the update and voila! I was stuck with what I was sure was now a very expensive brick. A couple of years ago, I made the mistake of not checking to make sure my laptop was securely plugged in while Windows was undergoing a major update.
Windows 10 is, on the whole, more trouble-free than its previous iterations - but sometimes, things just go wrong.