OK here's a weird one! For some reason, my computer has recently stopped playing the Vista sound when the logo 'shimmers' on startup. Everything else is fine. When I log on I am greeted by the usual bing bong...it is just the startup sound that is missing 
This isn't a massive problem and I guess it doesn't bother me that much, but I wouldn't midn knowing what, if indeed anything, is preventing this sound from playing.

This isn't a massive problem and I guess it doesn't bother me that much, but I wouldn't midn knowing what, if indeed anything, is preventing this sound from playing.
Now how did that happen? 