The Ontological Argument - valid or debunked?

[wiploc]

I think the most you can get from the argument is that God either necessarily exists or necessarily doesn't exist.

So long as you're clear that we're talking about necessary gods, then, yes, that's all the MOA proves. 

But if we go outside the MOA, and look at the definition of "possible world," then we see which of those is true. 

Since possible worlds include godless worlds, it cannot be true that necessary gods exist.  Because gods cannot exist in godless worlds.  Therefore, no existing god is necessary.  All gods defined as necessary are nonexistent.