New computer boots but monitor doesn't detect signal

[BMamba24]

Q9450
Asus P5Q Pro
OCZ700GXSSLI 700W
HD 500G|WD 7K 16M SATA2 WD5000AAKS
WIN VISTA 64BT
MEM 2Gx2|CORS TWIN2X4096-6400C5
VGA ECS N8800GTS-512MX RT
30" LCD Monitor

This is my first build which I started around a month ago.
I loaded windows vista and had all drivers updated for motherboard, VGA, etc.
My computer was up and running and the only problem was my Bios wouldn't let me update and save the settings. So I RMA'd my motherboard (love new egg) and just received my new own yesterday.
So after assembling everything I hit the power on my case and all of the fans come on, lights light up, cpu fan spins, vga fan spins, everything sounds like it is running but my monitor won't detect the signal. So I plug in my old crt monitor and still no signal. My computer sounds like it is up and running fine but I can't get a signal.
I searched on google for answers and tried a couple of things that I had seen suggested. I removing my motherboard from case and just left the power supply, cpu, vga, ram, and monitor connected. I hit power and still no signal but everything seems and sounds like it is working. I removed the vga and reinstalled it making sure it was tight but with no luck.

Please help!!!

 

[cavemangrinder]

Try a different graphics card.

 

[BMamba24]

I don't have another one.

And the graphics card use to work before I RMA'd the motherboard so I would hope that it is still ok.

 

[mr yoyo]

does the computer make unususal beeps when it boots ?

 

[BMamba24]

No I don't hear any unusual beeps?

 

[mr yoyo]

have u tried putting it in the other pci x16 slot on your Mobo?
u could have a problem with one ur pci xpress x16 slots

 

[Teny]

does your motherboard make post beeps when it starts?
usually a motherboard will make a beep when you turn on a computer, but if it doesnt, then there should be like a thing thats round and has one of the connectors like the ones for power on, reset, led, etc. It should be labeled as "Speaker" and i think it comes with the case.
if you got that little speaker thing, install it where you motherboard manual tells you, then turn it on. If it beeps once, then everything is okay, but if theres more then theres something wrong, and its easily analyzed by the beeps, and if theres no beeps, then theres something wrong with the mobo.
Or maybe just check all the connectors, sometimes we forget to plug something in. once i forgot to plug in the 12V power connector and had the same problem

 

[BMamba24]

I tried both PCI slots and still no luck

 

[IAntDemo]

try a new cpu

 

[wol-va-rine]

have u tried putting it in the other pci x16 slot on your Mobo?
u could have a problem with one ur pci xpress x16 slots

are you sure you plugged in the 6 pin pcie connector to the video card...? it's a pretty easy thing to forget...