This may be a silly question but have you tried passing the kernel acpi=off as a boot parameter? When I see X, sound and lock in the same paragraph my thoughts turn to turning off acpi.
Maybe this'll help. Good luck.
BTW, I really like my Nforce2 Abit board but acpi and other issues drove me mad until I switched to the 2.6 series of kernels. Now I be happy ;-)