Guys: Haemo is right. As we've mentioned, nearly all of us on the MSI RD790 had the problem when:

-CPU set voltages too low: sub 1.2V
-RAM voltage was set too low: 1.8V
-RAM timings too low for the volts
-You chose 1066 mode.

The board looked dead no matter what you did. You needed to only leave in one stick of RAM, vid card, no HD, minimum fans and bootup after clearing CMOS for 15mins and leaving the system off for 8-9 hours. Then it would boot, you could set the right settings in the BIOS and add everything back in and everything would boot perfect. before this, you need to check power lines, specifically the +12V rails (all of them) at bootup to see if they're within ATX spec.

Sadly, I doubt it was the boards problem and I think you're going to have to deal with it again if you get a new board since the first three problems I outlined could also be affecting you as they've affected many.

*Only leave in 1 stick of RAM. Two put stress on the IMC and need higher CPU volts for stability.
*Set timings to 4-4-4-12 tRC 30 tRFC 105ns 2.2V 1:2 divider (800) when you get in.
*Check VCore, it should be above 1.2V, if not manually adjust it up one notch (as a test).

Then when you get into Windows, stress test the hell out of it to find any instability. Stock stability testing is the first thing you should do when you get a system built.