The summary indicates that the music is played by the BIOS to indicate that the CPU fan is failing. I would have thought that it would be better to just play a warning beep; having music play randomly is a bit weird.
Once, a PC scared the shit out of me because the motherboard started talking at bootup (was a feature of Asus motherboards). But at least it was recognisable as an error message, just having music play randomly would be even more weird.