Another thing you can try is cleaning out the fan and heatsink... often these will get clogged with dust and the fan has to work a lot harder to cool the cpu.
On my old laptop the fan was on constantly until I cleaned it, now it only turns on when I'm playing games etc.
In some laptops, the fan/heatsink is accessible under a panel on the bottom of the laptop, which can be removed by a couple screws. If it's *not* accessible, don't bother trying to take the it apart to get at it, it's usually more trouble than it's worth. Just blow a can of compressed air into the vents instead.
I dropped my laptop (well not drop) it was in the laptop bag but I forgot to zip it up, and I lifted the bag and bang, my heart hurt. I got an error when I tried to reboot but it worked after the 2nd try...
