When someone asks me something that includes some reference to a god...anything about any god...my thought process immedately equates the question with asking a mathematician to divide by zero.
It is very hard to get a believer to understand the position of a non-believer. They find it difficult to understand how the their claims of a god's existence could be denied. There have been some nice analogies put forward over the years to try and get people to understand. (My favorite is calling atheism a belief is like calling bald a hair color.) But they are usually just dismissed as irrelevant and ignored. The believer then just continues their pre-programmed diatribe as if they've heard nothing at all.
For me, the best alternative is to say something that would simply stop them. I don't care to get them to change their mind; I just want them to shut up. If they end up thinking, then fine. But I don't count on it.
The analogy I've come up with is that telling me that I have to accept a god is like telling a mathematician to divide by zero. It's a nonsensical mathematical claim that most people have heard about and can hopefully understand. If I don't give their initial claim the weight of being valid in the first place because of its nonsensical nature, then it's hard for them to get past it. They can, like other claims, just ignore it. But I can just keep repeating it until they understand there's nowhere to go from there. The conversation is over.
This is, of course, an analogy, which proves nothing. It is simply a way to try and get someone to understand a little better the stance I hold.