This sound is a user-made parody rather than an official Microsoft chime, created by whistling the familiar startup melody instead of playing the original electronic version. Parody startup sounds like this circulate widely on soundboards and in short videos, where creators use them to mock outdated technology or surprise viewers who recognise the tune instantly. Because the Windows boot-up sound is so widely remembered, even a rough whistled version reads immediately, which keeps the clip useful for jokes, edits and reaction content long after the original systems fell out of use.