Hi,
Particularly as there's no sound from tapping the keys in the Bios Menu ( where there's no Windows driver involved ), it does look like a hardware problem.
As a further test, try the following.
1. Create a bootable Ubuntu CD - a guide on creating an Ubuntu CD and the download can be found Here.
2. When created, follow the guide on the link below to Try Ubuntu.
http://www.ubuntu.com/download/help/try-ubuntu-before-you-install
The 'Try Ubuntu' option runs the OS from the CD without the need to install on your HDD. It will be slower than normal running from a CD, but check if you have any audio output.
Regards,
DP-K