It doesn’t, until you install various auto update/preload agents, bloat your shell extensions (popup menus, preview, etc), install “antivirus”, browser plugins,

It doesn’t, until you install various auto update/preload agents, bloat your shell extensions (popup menus, preview, etc), install “antivirus”, browser plugins, ram eaters, iops eaters, and so on. Windows can work for years without slowing down, but sadly that requires expertise to maintain. All my relatives who ask to “fix” their laptop don’t have it. And all I do to make them happy is clearing hk{cu,lm}/…/run{,once}, uninstalling “additional useful” software, and that’s mostly it. No background activity - no slowdown. Sometimes very weak windows computers fall into an update loop when they can’t install updates in one session and are turned off before they have a chance to break out of it. In this case I recommend leaving it on for a day (night), for it to do everything it wants to.