I can't help you with the BIOS, since the fact you got it from a company, may mean its locked, unless theres a way past it
But, yeah, there is a safety limit on CPU's.
GPU's can reach around 100-110-119 degrees C before temperature starts to become a problem. You'd soon see the problems though if they occured.
A CPU on the other hand, I wouldn't let go past 60 degrees C at full load to be honest. My quad gets to around 52 degrees C on all 4 cores I believe... pretty hot, but its not a problem in that sense.
A note though: The hotter the component, however safe, the less time it'll last.
But in terms of lasting, it'll still last longer than you'll probably want the parts for anyway, IF kept at reasonable temps.