I'm hesitant to think that it's the kernel emitting the beep. Boot to single user (Rescue Mode in grub menu) and try these keys from just the command line. If you still get a beep, then mark this bug Confirmed/Medium/Assigned to ubuntu-kernel-team.
Otherwise start checking the apps in the desktop environment you have. ** Changed in: linux-source-2.6.20 (Ubuntu) Status: Confirmed => Rejected -- Volume up/down keys cause loud beep on some ThinkPad laptops https://launchpad.net/bugs/90818 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs