My mother, 66 and moderately IT literate, phoned me in a panic a fortnight back. Her little Win7 box, custom-built on a budget about 5 years back and running almost bugger-all aside from Chrome and a few lightweight hidden-object games, was running slow and spitting low-disk-space errors.
I RDP'd and took a look. The drive is a 120GB rust-spinner partitioned into two volumes for System and Apps & Data. System had grown by about 9GB and now sported a weird Windows.~BT folder, which was the source of the sudden bloat. It was also locked so hard even Administrator couldn't delete the thing - I had to use 'Take Ownership' to be able to nuke it.
I cleared-out the GWX KBs (she likes Win7, thought Win8.x looked abominable, and sees nothing persuasive about Win10) and tidied up. All good, until a few days ago when she called again with the same symptoms. Win10 was back, and short of poking a dangerous hole in my firewall and letting her PC partake of my WSUS governance I'm not sure I can keep it out. So she's probably just going to turn Windows Update off. Good job, Microsoft!
Back at my gaff and in parallel to the above, I took a few days to mull it over and dispassionately consider the pros and cons.
Then precisely a week ago I plugged a newly-created Ubuntu boot stick into my laptop, and without a moments' hesitation let it blow the Windows partition away, reformat, and install itself.
I'm running my applications either as native Linux versions or Wine cuckoos. Everything works.
Sure there's a learning curve ('sudo apt-what the heck? aargh quick Google') but on the whole I'm getting the hang of it. And importantly I feel like I'm in charge of my computer again.