Gigabyte GA-EP43-UD3L Wont Boot / POST

Hi, I have just purchased a new system and after setting it all up, it wont boot at all.

What happens when I turn the machine on is:

1)My monitor displays nothing (it's status light stays amber although its 'connect to source' message goes away)
2)The motherboard makes no sounds at all (no beeps etc)
3)The cpu fan try's to spin but fails (it 'judders' once then stops)
4)The motherboards phase lights are green, green, yellow, red for about 5 secs then turn off
5)My keyboard numlock icon lights up.

The steps that I have taken to diagnose the situation is:

1)Ran the system with 1 block of ram (trying all the ram slots)
2)Ran the system with only the cpu, gfx card and ram - in the case
3)Ran the system with only the cpu - out of the case (check for shorts)
4)Used the 'Reset CMOS' jumper then tried all of the above 3 steps

Every test I have done produces the same results (top list). Is there anything that I am missing / doing wrong? Or is it a case of Dead On Arrival for the motherboard??

Any help would be greatly appreciated as I am completely stuck (I have built quite a few machines before but am no expert).

The system specs:

MOBO: Gigabyte GA-EP43-UD3L
CPU: Intel Core 2 Quad Q9650 LGA775 'Yorkfield' 3.0GHz
RAM: Corsair Dominator 4GB (2x2GB) DDR2 XMS2 PC2-8500C5 TwinX
GFX: PALIT GTX260 SONIC OC Edition 896MB
PSU: CoolerMaster 600W Silent Pro
HDD: Western Digital WD5001AALS 500GB