I have a dual boot system with WinXP/Ubuntu. When I boot to Ubuntu there is no sound. I ran alsamixer and the default sound card is the on board audio even though I have it disabled in BIOS. There is an option to switch the sound to the SB2. I switch it but still no sound. Rerun alsamixer and the onboard audio is back as the selected sound card. How do I get it to switch?