Computer blows when playing CF

I'm sure you know but when doing something which is more processor intensive such as play a game the CPU gets hotter so the fan get faster to cool it down. (This is usually automagic but can also be a specified fixed speed).

If the heatsink and/or fan is clogged with human remains (dust), cat hair, bits of fluff etc, the fan will have to work even harder to keep the CPU cool. Cleaning it out (especially if its a laptop) is not recommended for beginners as you could damage components.

If you have a desktop PC (or high-end Laptop) your graphics card will be doing the same. Some (most?) graphics options have an option so you can adjust how fast the fan is going which sometimes is actually far to much. My fans default is 100% when it gets to a certain temperature when in actually fact it only needs to be about 50-60% to keep it cool enough.

Getting the right fan speed though is not just a case of setting it to a low setting, you need to be able to see what effect it has on the CPU and/or GPU to get the right balance between processor speed, fan speed, loudness and performance.

Viewing and setting the fan speeds can be done with a variety of fan speed monitor software (and hardware). Usually the software can be supplied from the maker of the CPU/GPU in question.

DON'T TURN THE FAN DOWN TOO MUCH OR YOUR SYSTEM WILL GET COOKED!

Your graphics card needs to be cooled unless you want it to overheat and break