As far as the bios, you may have to use a utility on the motherboard CD to update the bios, but need to download the bios update directly from the website. Depending on how far behind you are, it may or may not be necessary. Many times a descriptive file is included that explains what has been addressed in the bios. If it isn't anything that might effect you, then an update may not be required.
Hard to say what might be causing the problems, but conflicting drivers might be involved. If you disable the on-board sound in the bios and uninstall the drivers and the device in device manager, it may help.
If you can't get if figured out, you might try removing the SB drivers, uninstall the device in Device Manager, and remove it from your system. Then re-enable the on-board audio and load its drivers for testing.