my athlon xp 2400 is overheating when i start putting demands on it and it shuts down. when i try to do a backup or play an audio cd the temp starts rising to the point whee system shuts down. the heatsink is the original athlon heatsink that came forom amd. system is fine just sitting there. i added the hardware monitor that came with the dfi motherboard and cpu temp sits around 54 c, as soon as i start taxiing the processor it goes well over 90 c according to the monotor.