It is VERY annoying! You can decrease its volume using system volume. It is not any sort of sound file. At least I haven't found anything... It must be the PC beep!
In my earlier Fujitsu-Siemens laptop I had the same trouble, but I had "PC beep volume" in my sound card. I just had muted it and it was gone.
By the way, in the earlier model it wasn't so annoying. It was a simple "beep" while in V5505 it is a "BEEP
Why isn't there any "PC beep volume" in the newer V5505?
I hope Fujitsu Siemens / Conexant will release new drivers to change it.
Anyway, if someone knows how to do it please write!