It might be worth checking for fluff etc in the air intake. I find on my current laptop, Surveyor doesn't normally have the fan working that hard, as opposed to RW when I was doing something the other day in the route editor it was on full blow and I could smell the heat!
Years ago I had an old Toshiba laptop which I used with the MSTS route editor and that used to get so hot, eventually the heatsink peeled off the CPU!