Atheists, what mechanism do you use to positively say God doesn't exist?

There is no shred of evidence that any god/s exist. I am a nonbeliever b/c no evidence has been given.....I am not 99% or 80%, BUT 100% a nonbeliever....until evidence is given. Then I will verify said evidence, and if found worthy and credible, accept....though, I still wouldn't worship your murderous version of god.