The point of the question wasn't specifically aimed at telling him to get a speaker if he didn't have one. It was specifically aimed at narrowing down the possibilities. As I mentioned above, if he doesn't have a speaker, but his LCD poster is working perfectly (which is controlled by the motherboard) then there's a very real possibility that the motherboard is fine. If the motherboard is goosed, then the likely hood of the LCD poster working is slim to none. Asking about the speaker was a way to help support that thought. If on the other hand, he did have the speaker installed the whole time and wasn't getting any beeps, then yeah, the mother board could more likely be the problem. But he doesn't, so the likely hood of the motherboard having the issue is considerably lower. Meaning the problem is most likely the graphics card itself. Not the drivers, the actual physical graphics card is most likely failing. This explains the graphical artifacts. The fact that he can't boot into windows. And even windows installer as if the card is faulty in a major enough way, it would easily crash the computer trying to run any graphics. I've had a graphics card fail before, and it was similar issue to his, except I could boot it safe mode. But just because I could boot into safe mode when my card died doesn't mean he will be able to.
In short, based on what you described through the course of this. The symptoms, and the things we've checked, I highly doubt the issue is with your motherboard in any respect. It doesn't fit the nature of the problem your describing nor does it fit if your LCD poster is fully functional and no beeps because you don't have the speaker plugged in. I think the problem is with the graphics card. I know you said you don't have a spare graphics card. But if you have another computer that uses a PCIe graphics card, I would highly recommend you borrow it from that computer for about 10 - 15 minutes to test if the problem is coming from the graphics card. With the given information, the most likely culprit is the graphics card as it is the only thing that fits the symptoms and the information we have at hand.
Final Note: I also see that you've already reset your CMOS, so it can't be the overclock, because you've already wiped the overclock settings.