DFI Forums - NF4 Ultra-D - 1 LED hang on 702-2. After hours of debugging, it turns out all these problems seem to be from a failing "OCZ PC4000 VX":http://www.ocztechnology.com/products/memory/ocz_el_ddr_pc_4000_dual_channel_gold_vx memory stick. Finally did a swap for some OCZ 3700 Gold Rev 3 and it booted fine and found there was one good one and one bad.
So the lesson is that if you suddenly get blue screens and funny failures, sometimes it is really a hardware failure. For the record, I've had over the last six years, three hard disks fail, now two sticks of memory. Now I am overclocking and the like, so I'd expect to get more, but it means that if you suddenly start to get strange things happening, you have to go back to the beginning as a do-it-yourselfer and debug with just a graphics card, CPU and a single stick of memory.
So on to getting more Ram, maybe the 2GB sticks are right. By the way, "OCZ": has a great forum on settings. Also other things I've learned in tromping through DFI-Street.com a few things you need to know:
* DFI LanParty likes TCCD and not CH-5 apparently, so looking for that makes sense for something else.
* DFI is made to overvolt the Ram, in fact, it can go up to 3.5V, but the tradeoff is that some folks think that really blows the Ram after a while. I'm a poster child there. The TCCD memory apparently doesn't need such overvolting.
* The BIOS is versions are complicated, but basically, the latest version is 704-1 for generic Ram, 704-2 for CH-5/UTT ram that you put into the yellow slots and 704-3 for TCCD that you put into the Orange ones.
Final lessons are the various keys you hold down when you boot the system:
* TAB. This gets rid of the splash screen so you can see the POST
* INS. Hold the insert key down and you boot with "safe" memory timings