MSI Neo2 Sound disabled when OC

[lbbond]

When trying to Overclock the MSI 865PE Neo2 to even as low as 112 FSB from 100 MHz, the onboard sound device disappears from Windows XP HW devices. Restoring the default clock will restore the sound back. Any Help?
P4 1.8 A
MSI Neo2 865PE
BIOS version 1.5
RAm: Hynix 512-400
MAxtor Disks 40GB