Atheism isn't a belief?

Yes I am an avowed atheist. In my interpretation of my atheism is that there is no god. Never has been, never will be. To me it is not that I don't believe in god, it is that I know there is no god.Atheism is at times broken down in two pieces. They are called weak atheism and strong atheism. Weak atheism is defined negatively as the absence of belief in a god. Strong atheism is defined positively as the belief that a god does not exist.Therefore, I think to continue this thread two things have to happen.
1)what the definition of a belief is.
2) Determine why it is so important for the theists to say atheism isnt belief.Definitions say atheism can be a lack of belief or a belief.
Discussion over??

I know what I know from proof. There is no such thing as the supernatural. The idea of the supernatural goes against everything that can be proven and shown. The natural world exists. We see it, touch it feel it every day. There is no need for me to have to show there is not a supernatural. The onus is on the believers of the supernatural to provide proof.

All three are true

I dont know enough about the world of physics(quantum, partical or whatever) to explain the creation of the universe. Your question implies a couple things.1)That there is a first cause
(I am not willing to agree that there was a first cause. My feeling is that there always was something and alwys will be something. No end no beginning. I have no proof but there is no proof of a beginning either.)
2) That if a person does not believe that there was a god as the first cause, then they have to say what was the first cause. The lack of a natural explanation does not automatically bring us to the conclusion that "Therefore, there must be a god". It just means we do not know. This is not an either or proposition. Just because something is not explainable (at this time with present technologies) does not automatically mean there is a god.