I don't understand how they can do this. The startup sound is just a .wav file stored on the hard disk somewhere. On my windows machine, I found this file, and replaced it with something more to my liking (an excited chimpanzee). You could also replace it with a silent .wav file...
I thought that too, but if I wanted to make it impossible for someone to change it or turn it off, I'd embed the sound in .wav format inside one of the system files. Can still be hacked, but it's not as trivial.
or, as I had on my old computer, the Looney Toons opening theme for boot-up, and Porky Pig for the closing theme...
They could code it into the OS kernel. It wouldn't be the first time a marketeer left the engineering department with bruise marks on his throat.
Be careful not to create a silent wav file that is 3 minutes 33 seconds long, else RIAA will be banging down your door for unauthorized use of a copyrighted song.
Can't remember the fellow who "recorded" 3/33, but he passed on recently. IIRC, he also wrote a "symphany" that is supposed to take a couple of hundred years to play.