No Response from System Dilemma

I was building a new computer yesterday, I include the specs for the sake of it

Point Of View 8800GT
Intel Core 2 Duo E8400 Boxed Processor
Maxtor STM3320820AS 320GB
Coolermaster Centurion 534
ASUS P5KC AiLifestyle Series iP35 Socket 775
OCZ 2GB Kit (2x1GB) DDR2 800MHz/PC2-6400
Hi-Power Black 800W Modular 13.5cm Fan PSU - 4x PCI-E, 20+4pin, 6x SATA
Arctic Cooling Freezer 7 Pro
LiteOn 20X SATA DVD±RW/RAM
Sony 3.5" Floppy Drive

After finishing, I press the power button but receive no response from the system whatsoever and no beeps either (I have the speaker connected correctly). The only thing I heard was a very faint and hard to describe buzz that lasted for a quarter of a second when I would push the power button, but it only happens once.

I'm sure that I've connected the power switch right and I'm also sure that the ATX 24 pin and ATX 12V 4 Pin are both in securely, there's an LED on the motherboard called SB_PWR which lights up indicating power is going to the motherboard; but the problem is I can't get a response out of any of my devices, including the case fans which are plugged directly into molex connections from the PSU, surely if it was a motherboard issue those fans would be spinning because they're plugged directly into the PSU. (The PSU is an ATX PSU by the way)

So my dilemma is, if it's a PSU problem why is the LED on the motherboard indicating power by lighting up, and if it is a motherboard problem why aren't the case fans that are plugged directly into the PSU spinning? Initially I thought it was a CPU problem but now I just have no idea, obviously the 800W would be adequate for this system configuration.