I was here with exactly the same problems about 4 months ago on my 2 year old x58a-ud5? i think it was. Anyways, this time its the X58A-UD3R only 4 months old, everything has started breaking or getting out of date in the PC. Just lost 1 of my 2 SSD hard drives (120Gb now its a useless paper weight lol), it was 2 years old, replaced it with an HDD 2TB Western Digital, and just updated my GPU from a Nvidia 295Gtx to an ATI HD6950. Now whilst playing a game, it just switched off... no warning, nothing. I thought a power cut. But other things were still on, and then it wouldnt restart at all. When i opened up the PC, the fans spin at 1st start up from cold... but nothing from a restart there on, unless you power off completely at the back switch and then turn it on again, same thing, fans spin 1 second... off and nothing.
So im running:
Win7
X58A-UD3R
I7 940 2.93Ghz (No O/C)
6Gb Ram
ATI HD6950
1 x SSD (120Gb) + 1 x HDD (2Tb)
Ive tried the reset BIOS button, im going to try the battery out too for good measure and i can try old GPU tomorrow... otherwise im at a loss why another motherboard spins fans for 1 sec. Has no warning beeps, does have a few lights on the board, but doesnt start up to at least the bios screen. Any Ideas???