Google for an overclocking guide and check to make sure the resistors on both sides are set how they are supposed to be.
_________________________
MacBook Pro, 2.2GHz SR Core 2 Duo, 120GB HD, 2GB RAM,
PowerMac G5, DP 2GHz, 2GB RAM, 1x500GB HD, Sonnet Tempo X4P, 2TB RAID, ATI 9650 256MB.