Have 2 new DX58SO MB. with I7 920 & I7 975 using 12 GB Triple Channel memory 1600. Cannot get a post boot. Have 2 Video Cards, Radeon 5770 & Gforce 9600GT. Using Antec 650 earth watts.
Are you getting any beeps? what is the CPU fan doing? does it spin up and then stop or continuosly spin? do you get any beeps without memory?
Aslo what is the SL of the 920 and the AA of the motherboard, from the little info you have given i would guess that you need to update the BIOS http://processormatch.intel.com/CompDB/SearchResult.aspx?Boardname=dx58so
For the 975 and one of the 920s you need bios version 4021