That is only an approximate value, that came from looking at different sites oppinions but i'd say that in celsius, you are risking of really damaging the CPU/killing it, and thats what i meant really, and so at the point you should definetly turn off the pc and change the heatsink/fan lol. I'd say 55-65 is more a safe range in celsius for processors to run at
As i said though, you'll find pentiums have really good protection against that, so i wouldn't be too worried. If it is too hot, you'd more likely be suffering from lower clock speeds than damage.
If you go to Control Panel, System, just check that the clock rate is running as it sould be, and hasn't dropped but i wouldn't think at you're temperature it would have started the protection feature yet at all
Hope I have Helped
Kage