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I'm sure it doesn't help, but even with all that stuff disabled it's bad. svchost.exe's mysterious machinations, windows updates, superfetch (or whatever they call it now), one drive syncing, malware checking, app updates, it's like 'everything everywhere all at once' for Windows. You can make a case for all those things, of course. Just why does it have to launch into them all immediately upon startup? On a beefier…
Recent versions of Win10 still perform quite well on old hardware for me - could be that you just need a clean install?
I think what the main problem was they hadn't used it in a while and accumulated a backlog of mandatory Windows Updates. While these chugged away they got frustrated with an almost unresponsive computer, turned it off, install interrupted for the same thing to happen all over again. I can see how doing this stuff in the background makes sense as you don't necessarily want to bother the user with it, but when it impacts performance so badly maybe it's better to throw up the message and the progress bar. At least they know what's up!