Since you have a mobile, yes and no.
It has PowerNow, so you would be able to change the multi and voltage while in Windows with something like CPUMSR.
However, the nForce2 chipset the NF7-S uses doesn't support PowerNow and the system just freezes when you try to change the multi or voltage, so no.
If you had a Via chipset board, you could. You can use nTune, Clockgen, or Speedfan to just lower the FSB and then lower your cpu fan speed if you have a way of doing so.