[mike182d]

And why is the first cause argument any good at proving god? Who created him?

I think you need to analyze the argument a little better. No one created God, nor does the argument suppose that everything created has a creator. The foundational premise is that there are two modes of existence: contigent or necessary. The existence of everything in the universe is contingent. The whole of all contingent matter cannot account for its own existence for the sum is never greater than the whole. Thus, there exists a necessary being necessarily.

The argument never says that everything has a creator. That would be absurd.