Overheating

My client's laptop has been overheating a lot.
She says when she has it on her lap it burns her leg, when she has it on a table, it gets very hot as well.
Disk tests and memory tests are fine, and the Event Log says there's nothing out of the ordinary.
Because it's a Dell Inspiron 1200, lots of CPU performance monitors don't work with it, so I downloaded the one specific to Dell.
The CPU temperature is 60C, the disk temperature is 38C. With that software, I can force the fans to run at double speed, but then that hampers performance.
She only uses it with the power supply plugged it.

Systems specs:

Windows XP SP3
768MB RAM
40GB HD
Dell 0FD381 motherboard
Dell A05 21/6/05 BIOS
Intel 915GM Chipset

 

I think those are quite normal temps for a laptop. I once tested the CPU temp on my laptop and it was over 70C. Laptop CPUs can safely reach almost 100C.