Patton3 would be correct. As much as I'd love to say "there is no god" I, nor any one can specifically be sure that there is absolutely no god. However, the possibility of the existence of one is so incredibly illogical that we can still rationally assume that there is most likely no god. Which would make me an agnostic atheist.
Unfortunately, we can't disprove a negative. which makes "prove that there is no god" impossible to prove because there is no physical evidence of one. However, we can prove an Idea of god as incorrect.
Let's say that someone believes in a god that is Omniscient and omnipotent (all knowing and all powerful). We can disqualify this as possible due to the fact that these two forces clash. You can not know everything and still be all powerful. Take as an example a being that knows the outcome of something, does it have the ability to change the outcome? if so, then this being didnt really know the outcome if it changed it. So the being doesnt have the power to change an outcome of something it knows the outcome of.
There for the believe of ANY deity that is said to be all powerful and all knowing is therefor a false view of a deity as it is absolutely not possible.