Computer won't start, board posted, but heatsink fan not spinning

Going crazy...please help.

I built my new computer last night, however it won't start. There is power to the motherboard, because I can hear and see the fans when I turn it on, it also beeps when I pull the graphics card so I think the board posted OK, however the Heatsink fan doesn't move. It initially spins a rotation or two and that is it. It does the same thing when I power it off, just a initial spin or two and then it stops. Any ideas...I would be so grateful. Here are my system specs.

One thing I did notice on the power supply, and I'm sure this is normal or not, but on the 24 pin connector (the PSU has a 20+4) I noticed there is no wire going to to one of the pins, it is just blank, that could just be how it's supposed to be though

Intel Core 2 Duo E6750 Conroe 2.66GHz LGA 775 65W Dual-Core Processor
GIGABYTE GA-P35-DS3L LGA 775 Intel P35 ATX Intel Motherboard
Rosewill RP550-2 ATX12V v2.01 550W Power Supply
4stick of - G.SKILL 1GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
APEVIA X-JUPITER-JR G-Type X-JPJGT-BK Black SECC Steel ATX Mid Tower Computer Case

Thanks so much for your hel!!!, It's been a while since I've built a system..so frustrated!

Dont let that fans lack of movement distract, most HSF just "wiggle" once when the board is not functioning properly.

Process of elimination, start removing non essential parts and see when you finally get a solid boot.

And I personally do not know, make make sure that the board's current BIOS supports your chosen CPU. It should, but something to keep in mind.

EDIT: But do what mweidler said first. Im bettin that is the problem!

Hey the same thing happen to me, and it was strange,

Result that the problem was my memory, try putting one stick of memory at time and see if its post, it work for me.
Try that and let me know.

After 6 months one stick of my Crucial ballistix PC6400 got damage and, I just quit it and everything is fine now, except that I only have 1Gb instead of 2GB.

Who knows what happen.

Also I read some reviews on Newegg and this happend to a lot of people in all brands.
Corsair, kingston, crucial, g.skill,mushkin, patriot,etc see it by yourself.

Sorry for me english im Working on it.

My system is E6750
GA p35c-ds3r
2Gb crucial ballistix
8800gts

Almost the same system.

believe me it works for me Try 1Gb at time maybe is one memory stick that is bad

Your problem might be that you have a crap PSU that just is no good.

That'd be my first guess.

Then I'd might try RAM. But I'm betting you got a junk PSU from a junk manufacturer.

I had a similar issue when I fired up my new build for the first time yesterday. I originally connected my 3 pin heatsink fan connector to the 4pin CPU fan connector on the motherboard like you did. I figured one of the pins just wouldn't be used. But when I powered everything up the heatsink fan wasn't spinning.

I moved the heatsink fan connector to a 3pin SYSFAN1 connector on the motherboard and it worked fine.

Have you tried testing it out the box like mweidler said? hes completely and utterly correct. this eliminates shorts from the case and allows for quick testing and trouble shooting and it not that much work.

On the ram side of things start with one stick first and then move up.
this happened to me once because my frontpanel wires where shorting. also one unpaired ram can result in problems like this in dual channels so i hear...

Good luck