The sound comes from Microsoft Windows XP, the operating system released in 2001 that defined home computing for a generation. Its startup and shutdown chimes were heard daily in homes, schools and offices, becoming as recognisable as the green hill wallpaper. As XP was retired, the clips survived online in compilations, remixes and meme edits. The shutdown chime in particular became shorthand for powering down, logging off and quitting, which keeps it popular in gaming, tech and reaction videos today.