You might be getting a false positive. Does it crash when it reaches 100C (Wow, that's hot!) or just reach 100C? Could be a sensor malfunction. Is the CPU fan running? The only time we've seen temperatures this hot was with a computer with no thermal compound. PC are equipped with automatic temperature cut offs if your running this hot this feature isn't working.
How about a OS, computer brand and model when you respond. What CPU would help as well.