Need help with new build

[RunsLikeMad]

Sorry if this is in the wrong forum; not sure where this belongs.
Having bought most of the bits for my new rig - and the old ones too, from OcUK - and having trouble I thought I'd ask you guys for ideas.

Here goes:
Currently I have no video signal
It's not reaching POST
There are continual long beeps.
All the fans and hard drives are working.
Depending on which PSU plugs I slot in it takes one or two presses of On to start.

Specs
New bits:
Asus P5N32-E SLI motherboard
BFG 8800GTX
E6600
Arctic Pro Freezer 7 or whatever it's called.
4GB (4 x 1GB) sticks of OCZ PC8500 RAM
Corsair 620w PSU
Creative Fatality X-Fi
Dell 2407 monitor

Old bits:
Raptor HDD
WD Caviar HDD
2 x DVD-RWs


I plugged it all together, turned it on to get one long loud bleep.
Removed the floppy cable to get the continual long beeps, which is where it is now.
Tried the PSU 24+4 - no luck. 24+8, no luck. 24 alone, no luck.
The 8800 has both power connectors installed. Removing two of the RAM sticks is no help.

 

[BillytheImpaler]

Problems like this usually come down to faulty RAM. Take all the optical and hard disks out then remove all the RAM and try each stick by itself. If it never works it might be a faulty motherboard.

 

[RunsLikeMad]

That's one of the next options.

I am right in using the 24 + 8 power connectors, aren't I?

 

[BillytheImpaler]

I am right in using the 24 + 8 power connectors, aren't I?

Certainly.

 

[RunsLikeMad]

Why is the 8 pin ATX socket half blanked off if I need to use all of it. There is a four pin plug on the PSU. Does that have a purpose I need to know about?