first VERY carefully bridge your L1s with a mechanical pencil...that trick is explained in the O/C tricks section of this site.......then go into your bios and change the Athlon speed to manual or something of that nature, then you will be able to change your multiplier
CAUTION!!!!! DO NOT CONNECT THE WRONG L1 BRIDGES, it will most likely fry the cpu (but connecting the L1 bridges in easy to do and takes about 2 minutes if that)