New build HELP mobo leds but no boot, then boot and powering down few seconds later

When I hit the power switch it gives me all four phase led lights on the motherboard, all the fans are going, but it seems to be stuck in that position, no boot-up sequence, no signal to the monitor, nothing.

If I hit the reset power button, sometimes it does nothing and continues to be stuck and I have to turn the power switch on the PSU off. Occasionally when I hit the reset power button, it will go through the boot sequence and boot all the way to Windows Vista. However, after a few seconds the monitor goes blank, as in no signal to the monitor, and I am back to the place where I started, before hitting the reset power button (4 leds on the Mobo phase 1-4 all lit up, and the two indicator leds dark.)

This time (after it has turned itself off) when I hit the reset button nothing happens, when I hold down the power button nothing happens, I have to turn off the power to the PSU again. When I do this and wait thirty seconds or so, then power on and press the reset button it boots up but then turns off again in another minute or so.

What is going on here? It seems to me to be some sort of power problem where the board is powering down automatically for some reason. Could it be overheating and powering down because of that?

I have tried...
1) taking out a stick of a ram and trying each ram individually in various slots, same thing happens.
2) I replaced the power supply with the below, much more powerful one and it is the same.
3) breadboarding the system with no dvd/blu-ray drive hooked up, just hard drive and ram, same thing happens.

Also, when I installed the new power supply and powerd it up I did here some beeps, I wasn't really paying attention to them at the time, but now I cannot get it to repeat the beeps at all as in no beeps at start up. Any ideas? Thanks!



BIOSTAR TForce TA790GX A3+ AM3 AMD 790GX HDMI ATX AMD Motherboard

AMD Phenom II X2 550 black 3.1ghz dual core processor
Heat sink is stock that came with processor from AMD
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600)
SAPPHIRE Vapor-X 100269VXLE Radeon HD 4890 1GB 256-bit GDDR5
CHIEFTEC Turbo CFT-700-14C 700W ATX12V / EPS12V SLI PSU
SAMSUNG TOC T260HD Rose Black 25.5" 1080p monitor
Windows vista home premium 64bit edition
Western Digital Caviar Black WD6401AALS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive
hec Prime Black 0.8mm SECC Steel ATX Mid Tower Black Computer Case has one 120mm case fan
LITE-ON Black 4X Blu-ray Reader SATA Model iHOS104
Sony Optiarc 24X DVD/CD Rewritable Drive Black SATA Model AD-7240S-0B

Did you try removing the motherboard from the case and see if it willpower up then?

Is the motherboard under warranty? It may be time to consider an RMA.