Motherboard LED blinking green

[lightsx]

Just put a new computer and connected everything. I hit power and nothing happens. The led on my motherboard just blinks green.

I've tried reseting the CMOS, taking out the ram and putting it back in and unplugging the power supply. Not too sure what to do here. Any help is appreciated, thanks!

 

[Quiksilver]

System Spec's? Manufacture and Model numbers? What do the mobo manual say?

 

[lightsx]

Asus P5N-E SLI
Intel E8400
OCZ DDR2 800 2x2GB
EVGA 8800GT superclocked 512mb
OCZ StealthXStream 600w
Seagate 250gb 7200rpm sata

I tried to look for a troubleshooting section on the manual but I couldn't find it. However, I've tried googling the blinking LED problem and from what I've read it's either the PSU or motherboard.

Is there any other reason for the blinking LED? And if it is the PSU or mobo how can I determine which one is faulty without having to try another PSU? I don't have access to another PSU to try with.

Thanks.

Forgive me if I've left out any important details, I'm pretty clueless when it comes to all this.