First of all it depends on which version you buy.
There is one version that has a water block on it already:http://www.newegg.com/Product/Product.aspx?Item=N82E16814131335&cm_re=5970-_-14-131-335-_-Product
But as you can see, you will have to have the rest of the water cooled system ready to install this model.
All the other models found on newegg have a regular air cooled cooler.
That means that all you have to do is uninstall your previous drivers, do a driver cleaner in safe mode, shut down the computer. Then install the new video card and then power on the computer and install the new drivers from the ATi site.