|Is there a specific reason for overclocking, such as better gaming performance? If so, the 8400GS is an extremely weak card...no amount of overclocking can make up for that, plus you have the wrong RAM. You should be running DDR2-800. It would also help to know which CPU you have, there are several X2's that run at 2.1GHz...is it the 4000+?|
I just downloaded the manual & had a look at the BIOS section...it doesn't appear your board has the necessary options for overclocking.