That’s right; in order to bring your PC back from a crippling issue that was caused by Microsoft sending advertisements to it, you need to make a change to the registry.
The ad itself is for Microsoft Teams, and how it’s integrated into Windows 11. As with most of the ads that are injected into Windows, this should still pop up as a notification even if you have all notifications turned off.
While we know the cause, the bigger question that Aleksandersen dives into is how the Windows 11 shell can be so fragile that ads can crash it. Windows in 2021 has a ton of components in it that have to grab content from the cloud at any given time, from the Bing lockscreen wallpaper to Windows Update to advertisements that come from Microsoft. It’s pretty wild that when one of them isn’t functioning correctly, this could happen.