In my first post I said: "I didn't save my custom startup sound anywhere, it's only located in imageres.dll" which means that after I had loaded the sound into imageres.dll I deleted the sound file from the computer.
However I tried to do a 1033, 5080 and a .wav search from within "computer" and no usable results came up.
Basing on what you say to my responses, I'd assume you don't have a clue of where the sound file could be located at since it's not in imageres.dll.
I guess I'll just have to go through hours of searching the BBC's documentaries again