[Agent Steel]

Parts 1 and 2 can be read here and here, respectively:
viewtopic.php?f=23&t=167530
viewtopic.php?f=23&t=167955

Part III
The Moral Argument Against God's Existence

1. If God exists, then objective morals exist.
2. Objective morals do not exist.
3. Therefore, God does not exist.

First, it should be clear that the argument is logically valid. In propositional logic, this is known as Modus Tollens, or denying the consequent. I shouldn't have to explain why, as it should be intuitively obvious to anyone who isn't a total retard.

But are the two premises true?

A Christian is in fact forced to accept (1) as being true. If a Christian denies (1), he would in turn be denying that God is perfectly good. This would go against the very essence of what God represents for the Christians. If we accept that God is perfectly good, it must logically follow that his moral actions and moral commands are objectively good by their own nature. We can dig deeper into the truth of this claim if we need to. I will be glad to expound more on it if there are questions that need to be answered. For now though, I think it's safe to say that we can confidently accept the truth of (1).

What about (2)? Well first, let's examine whether there's any good reason to believe that objective morals do exist. To say that something is objectively true is to say that it is true independent of anyone's opinion. Now, this in and of itself is very curious. In other words, in order for something to be objectively true, we cannot rely on our own opinions to know that something is objectively true. Therefore, an individual who claims that morals are objective has no basis to make that claim other than his own personal, subjective opinion. In other words, the claim that morals are objective is self defeating. I think then, that we have no good reason to believe that objective morality exists. This needs to be expounded on much more, which I would also be glad to do for those who have questions. For now, I just wanted to lay out a basic outline for this argument, and give reasons for why the premises are more plausibly true than their negation. I’m aware it requires much more rigorous analysis than this, but there you go.

[One Degree]

1. If God exists, then objective morals exist.
2. Objective morals do not exist.
3. Therefore, God does not exist.

#1 is only true if you believe you understand God's message. You are confusing God with religion in making this statement.

[Agent Steel]

What do you mean? I don't understand.

[One Degree]

What do you mean? I don't understand.

Why do you believe God's existence requires the existence of objective morals? This is a belief of some, not a fact.

[mikema63]

You talk about not having good reason to believe objective morals exist but this doesn't really prove that they don't. I personally don't believe they exist either but I can't prove the source of morality one way or another. We can only buy into someone's argument for or against them. I don't think we can make absolute statements about their existence.

Or whether or not god actually cares about that sort of thing. At best premise one should be revised to the Christian god.

[Vlerchan]

1. If God exists, then objective morals exist.
2. Objective morals do not exist.
3. Therefore, God does not exist.

This is almost as close to definitional Begging the Question as one gets.

Therefore, an individual who claims that morals are objective has no basis to make that claim other than his own personal, subjective opinion. In other words, the claim that morals are objective is self defeating.

This is a non-sequitur for the reasons that,
1a. The claim that 'morals are objective' is a meta-ethical claim, not an ethical claim, and thus, even if we accept your abuse of the term 'objective' as valid, it is not clear that such a claim defeats itself. I can, for example, argue individually against each moral claim as holding no objective or subjective value (i.e. make claims about ethics)(the converse) and still hold to ethical nihilism (that there is no such thing as an ethical value, a claim about meta-ethics) as being true without the former statements invalidating the holding of the later statement.
1b. In other words, you are failing to recognize the difference between a claim about an ethic, and a claim about ethics.
2a. you are abusing the term 'objective' - and 'subjective', for that matter. If we take gravity as existing as an objective fact - i.e. it exists independent of whether we choose to recognize it neurologically or not; it existed before man, as a claim, for example - that does not stop us from claiming that gravity exists.
2b. if you are some weird anti-empiricist, or are against the use of gravity for some other reason, then replace 'gravity' with 'reason'.
3. As has been pointed out, you are also, at best, arguing against a great-mover that is also omni-benevolent.

Thus, your argument fails.