I want to study the behaviour of a Pentium 4 processor (with Ubuntu 8.04)
at high temperatures (around 80deg C).
However I cannot get to that temperature because the system shuts down at 60degs.
Is there a way in Linux to disable the shut down, or change the temperature at which the
system will shut down.

I have already looked in the BIOS, and found no way to do this.