Whether or not god exists depends entirely on how god is defined. It is always possible to define god such that everyone would agree it exists (e.g. god is the universe).
Since the dawn of time, humans have believed in tens of thousands of different gods and goddesses. The 
Encyclopedia Mythica describes over 6000. The evidence strongly suggests that all of them are fictional, in that they exist only in memetic form. Virions are atheists because we are skeptical.
If you are a theist, this may help you understand our position. We Virions are atheists for the same reasons you are an atheist with respect to the other thousands of gods and goddesses.
Visit the Secular Web.