Occurs with all that I have installed, all of which include a System start sound wav. Incidentally using the 64bit version of Win 7 as well.
I have been reading a number of sites which claim that changing the system start sound file on Win 7 is somewhat trickier, see for example http://www.sevenforums.com/customization/22429-how-change-windows-7-startup-sound.html,
Not sure how true this is
thanks for replying