You have got to hand it to Microsoft. No matter what version of Windows you’ve used, sooner or later it builds up enough junk—leftovers, temporary files, etc. that the system needs to be completely reloaded.
Windows 10 has done that to me on two computers so far. The latest one is telling me that the main disk is locked, which makes me believe that a reinstall won’t see my registration and will want me to purchase a new copy of Windows 10.
Oh, gee! How unlucky! I guess I’ll have to reinstall Windows 7– one of the few versions of Microsoft’s operating systems that worked reliably. Woohoo!