MS doesn't like Ccleaner and a trap for the unwary.
Main purpose of this separate thread is W10 and Ccleaner. Should one not load it.
One exec during a talk said simply: Don't. Said in a meaningful way. Lots on forums. Nearly all the gurus had used it for years.
I loaded it, but don't know enough to go into the Registry, and I think this might be the main issue. Anyway, MS say it is no longer necessary to tidy the registry. Personally, I still find Ccleaner cookie removal still seems to speed things up in 10, just as it did in 7 but now it's asking to close MS Edge cache database and IE, implying this is now active and milling about in our stuff even though using FireFox.
Horrible headache last night and forgot I entered msconfig while searching for cumbersome things loading. I altered the start procedure from Normal and totally forgot what I'd done thinking I'd done it with Ccleaner's tools or Task Manager Start. One heck of a trap.
Nothing I could do - not even pulling the power with no battery - would make it go into a 'Windows did not shut down properly' mode. Almost nothing would work (of course) with masses of warnings and no chance of recovery - nothing would load. suddenly remembered what I'd done but astonished no other method seemed to reach the problem while it was in a kind of safe start mode.