[newbie] CPU Temperature

[Al]

Hi All,   I have recently installed Mandriva 2005LE.   After about 1/2 an hour, it starts popping up windows saying "Your CPU temperature is too high, going to controlled speed"   I rebooted and checked the BIOS. temperature was over 70 deg Celcius.   So I went back to Windows (dual booting here) and downloaded a temperature monitor.   The CPU temp in windows never goes over 57 deg Celcius.   What's happening in Mandriva? and how do I fix it?   TIA   Al