This isn't to ask you which is the best water cooler. This is just to ask you how will running water around a PC cool it. The basics/theory/idea this is based on. And if you know tell me how liquid nitro cooling works (Although its a little easier to imagine )

go http://www.fastsilicon.com/showarticle.php?a=2
It's an article about water cooling from FastSilicon.com and even teaches you how to build your own water-cooling set.