You may als use a Linux-LiveCD (eg. Kubuntu 13.xxx) and start a terminal.
Sudo nvsetvol 0 should kill the chime.
Linux CD worked a treat thanks guys. Note to others ISO was 710mb and CD was only coming up as 702mb so needed to burn on pc using a DVD. I also had a lot of GFX corruption on the linux desktop but was not bad enough not to be able to select Xterm and enter the command. Thanks again my ears feel a lot better now.