There's a bunch of widely used programs and apps that run in the background and occasionally check for updates. Acrobat Reader, Steam and other similar game related apps, Discord, whatever... Hard to remember since my Notification Area is pretty sparsely populated. But I've often seen over a dozen icons there on other people's computers. Young gamers seem to have Steam, Epic, Origin, Nvidia Experience etc. there, older people may have TomTom, Common Creations, Teams etc. The common nominator for those is that they have a setting that prevents them from automatically starting when you log in. When set up so they don't automatically start a simple reboot before starting a game will shut them down if you've used them and left them in the background.
Then there's the less obvious ones running in the background. Allowing Windows notifications with sound and pop-up for all programs should be easy to spot but the Don't Disturb mode can hide the visible interference. Not to mention the less obvious programs running in the background: Edge and Chrome. Both default "Continue running in the background when closed". What's worse, Edge also defaults starting when logging in and loading the start page "for faster browsing". If you're using your Microsoft account for logging in, by default you're also logging into Edge - including Copilot. I don't know how much a system using Microsoft recommended settings actually listens to you but I'm sceptical about "Game mode" actually working for other than AAA titles preferably belonging to Microsoft's catalog.
