This used to happen to me, back when I was so scared of PCs that I still bought them retail, and the latest version of Poser was maybe P5? It would get so bad that Poser would always crash, leading me to suspect a problem with the models I was using at the time (they needed long render times).  Then I opened my PC to find it full of compacted dust, especially in the CPU cooler fins - the load the renderer was putting on the CPU during extended render times was causing it to get hot and the cooling fan to run flat out (hence the noise)- the dust was then causing it to overheat every time I ran a long render. 

Frightening how little I knew about PCs in those days!  I now build my own systems so aren't scared of them any more, and have no dust.  You might also check that the thermal paste which seals the CPU cooler/heatsink to the CPU hasn't dried out and become ineffective.  Pennies to put some new paste on there.

My self-build system - Vista 64 on a Kingston 240GB SSD, Asus P5Q Pro MB, Quad 6600 CPU, 8 Gb Geil Black Dragon Ram, CoolerMaster HAF932 full tower chassis, EVGA Geforce GTX 750Ti Superclocked 2 Gb, Coolermaster V8 CPU aircooler, Enermax 600W Modular PSU, 240Gb SSD, 2Tb HDD storage, 28" LCD monitor, and more red LEDs than a grown man really needs.....I built it in 2008 and can't afford a new one, yet.....!

My Software - Poser Pro 2012, Photoshop, Bryce 6 and Borderlands......"Catch a  r--i---d-----e-----!"