New Pc parts wont work correctly
I just bought new:

Motherboard:
Gigabyte GA-945GCM(X)-S2

Processor:
Pentuim D 945+ 3.40 GHZ
800MHZ FSB
Dual Core

Memory:
Corsair CM2X1024-6400 (2 Matching Modules

Power Supply:
Ultra "X-Connect" 500 Watt Power Supply.

Video Card:
EVGA E-GeForce 8600GTS

Problem is:
Put all the parts together properly, Power up PC and nothing shows up on my monitor screen. The fan on the CPU spins and The video card fan spins, appears that everything is getting power but no video on screen - this happens when I use the video card or onboard video - nothing on screen. Any suggestions to get me a video signal ?

Was the mobo purchased brand new or pulled from a 'Working System'?

I have experienced these symptoms on past builds and it has usually turned out to be a faulty mobo i bought second hand.

My bad!

Something to try is taking out one stick of ram. After this, try swapping them around. Sounds silly but it's been known to work.

Check all your connections carefully (all power cables inside & out of the case, drive connectors etc) a loose connection can cause this.

A CMOS reset perhaps?

Everything is brand new, Im going to try to return the motherboard and exchange for a new one. Is the memory I purchased compatible with the motherboard ?

looks like caperjack is right, you've bought the wrong ram. try exchanging it for pc2-5300 dimms

I cant agree....incompatible RAM will give you a series of error beep codes as your system will fail to POST.

If everything spins up and you get no beeps with just a blank screen, i would bet my bottom dollar on mobo failure most likely caused by ESD to onboard transistors!

Well i recommend you to exchange them as they are new and must be under warranty....

Power?

500w is a bit low for such a powerful cpu and a fairly decent gfx card.

Power would not be the issue here unless he is did not connect the cpu power. Or swapped the 24 pin extension for the mothereboard and the cpu power (don't ask).Also, some boards have a 6 pin cpu requirement while some psu's still use the 4 pin. My suggestion is the motherboard as well. But first, try resetting the bios by pulling the jumper, reboot and see if you get the post screen.