POST, then nothing

Here is my motherboard: http://www.newegg.com/Product/Prod [...] 6813128358

and my ram: http://www.newegg.com/Product/Prod [...] 6820231166

As the title says, the mobo gives a short beep post, i see the mobo splash screen, then it flips to black screen and stays there. The graphics card is still producing output, but its just a black screen. Ive actually successfully booted and rebooted quite a bit yesterday with both sticks in, and on the last boot i changed no settings, hardware or software, and shut it down normally through windows. Now this happens when i try to boot it up today. To get it to boot previously (booting has been a problem, but never quite like this) I tried just one stick of ram, and both sticks will boot the computer individually. I also did a memtest during that successful boot time (with both sticks in), and after multiple full passes memtest found no errors. Now ive read on here that it might be a voltage issue, but how did it boot last time then, even though ive changed nothing?

btw, I have flashed the most up to date bios, and i installed all the latest drivers for everything. I also tried loading both the optimized defaults and the failsafe defaults. I have no no overclocking of any kind, ever. I also have a 630 watt power supply that is brand new and way more than i need (dual core, 1 gpu, 1 hdd, 1 dvd burner). Where could i find the correct voltage if this is in fact the issue? Luckily i can still get into the bios settings at last check, but the way this thing has been something might change while its off...

Yup, as it turns out it was a low voltage problem. I went into my motherboard and found that the default setting was 1.8 volts when i needed at least 2. One other question, do i need to do anything to enable dual channel memory apart from putting the sticks in the right slots (i checked the mobo manual for the right locations and i am sure they are right for this).

EDIT: I just now noticed that in Easy Tune 6 it seems to think my ram is only PC2 6400 when i bought PC2 8500. It also says that its only 400mhz, is that normal?