Was just wondering if you looked at the control panel>power options if there would be anything in there. Would have thought the performance options in there will control the cpu speed.
I assume you have blown some air through the side vent, the copper fins can get a bit dusty and clogged (a good pair of lungs works at a pinch!). My experience with laptops has always left me wondering what they were thinking when they designed the cooling solutions, we don't all live in air conditioned clean room conditions
Bigger fans would be nice too, who cares about the noise. Sometimes you just have to bite the bullet on laptops out of their warranty period and remove the cooling to give it a good clean.
My sister's Dell machine is a good case in point, fins looked clear but after close inspection I found a perfectly hidden wad of fluff in the chamber between the fan and grill, was even black in colour.
Those little fan cooled laptop tray help a bit with marginal cooling, I keep meaning to get one for my old MacBook (always has got seriously hot but seems to cope, touch wood!)