Graphics card works in a motherboard, but doesn't work in another.?

Question

I have bought a new motherboard and case, seperated, I built everthing right, except the Graphics card which sits perfectly in the motherboard, but doesn't run. here are the things I've installed in the motherboard.
1GB RAM
Core 2 Duo and its fan
GeForce Graphics card
Power supply which have two sockets, one for itself's power and one for the monitor (Which I don't need) Monitor is already plugged into a socket.
there is power to the monitor, the PC starts, but the black background with the white writings on the monitor doesn't come up.
Hard Disk And DVD Drive haven't been installed yet, they're not important to start up the monitor.
Please tell me anything you know. Thanks

Monty

I thought more info will be alot in one question, but there:
Motherboard: Gigabyte-945p
Graphics Card Geforce FX 5500
Proccessor: Core 2 Duo 2GHz
RAM: 1 GB
Power supply have two power sockets one for itself, the other one is for old monitors (The Monitors that takes power from the power supply)
NO beeps, No screen display, power available to the monitor (Yellow LED) in front of the monitor (Stand by position)
green led infront of the case (Switched on) No Red Led front of the case.
I need to solve the monitor problem first.

Thanks

Answer 1

How do you know you got everything else right?

Do you get any beeps out of the system when you turn it on? If you have a bad graphics card then you should be getting some beeps at BIOS test.

No beeps probably means that you are not getting to the BIOS test and have some other processor or memory problem.

Answer 2

You need to be more specific: which model card, and which model motherboard. Since you say the card fits correctly, I assume you have the right format (ie: PCIx card with PCIx mobo) It could be anything- improperly seated card, incorrect voltage, a dead card... Is the mobo correctly connected to the power supply? Is there a little green LED on the mobo? If not, the problem is with your supply or mobo, but it's tough to say without specifics.

Answer 3

please give more detalis like the exact specification of your graphics card and your motherboard.enough