Below you can find some (older) IT and Security-related remarks, tips & tricks:

If you notice a novelty after your Win. 8.1 update - a task bar logo looking like this:

what's behind it is an offer to upgrade your (Windows 8.1) installation to Windows 10:

If you're not planning to do that do the following:

1. go to the Windows Update panel
2. click on "Installed Updates"
3. find and uninstall update KB3035583
4. restart the machine.
5. Done. 🙂

Notice: more info on this update from Microsoft is available here