Monitor blank screen

Hi everyone!

I just build a new system. The computer boots, I get no beeps and my monitor doesn't display anything.

SPECS:

Intel Q9550 Processor
Asus P5Q Pro Motherboard
Corsair x750 Power Supply
2 x 2Gb CORSAIR RAM
HD RADEON Sapphire vapor - x 4890
1To Western Digital Hard Disk
4 different huge fans in my chassis.

Monitor Samsung P2270 HD

Its very frustrating. Everything starts well but I don't get anything on my screen.

Monitor works well (fantastic oblivion with my old Laptop ATI Radeon x700 -still works).

I did try this system with a regular ATI RADEON HD 4890 (three red lights on 1601, 1602, 1603). I thought it was the graphics card. I replaced it with the saphire.

Now I get 1 red light (Ctf).

It is the first time I did assemble everything on my own.

I read the manual for my Motherboard. I have checked 50 times the cables and everything seems to be well connected.

And I did try to build my motherboard outside of the case with no success.

Questions:

Is it not good enough my system? Something is there I might not know that isn't compatible? I did some research before buying it.

What else is there I can try? Should I go for an NVIDIA? Is it possible the ATI and the monitor are not compatible? Do you think it is my motherboard?

Thanks a lot for your help...

have u made sure everything is plunged in right and that the power connectors to the graphics card r connected

well, ur mentioning the ram in the sockets, u will have likely 4 sockets, u would have 2 ram sticks, or 4, if u have 4 then ur fine, but if ur using 2, then yes they must both be in the same color slot, but also they will require the right colors, as a certain color must be filled up for an other one to be