Im having massive problems here and i hope ive just missed somthing simple.

This is my spec;
Intel Core 2 Quad Pro Q6600
Asus P5E Intel X38
Corsair 4GB DDR2 XMS2 Dominator PC2-8500C5
2x HIS ATI Radeon HD 4870
Western Digital Caviar Blue 640GB SATA-II
Creative Sound Blaster X-Fi Xtreme Gamer
Antec Nine Hundred Ultimate Gaming Case
OCZ ModXStream 900w Silent SLI Ready ATX2 Power Supply

Ive just put it all together and everything 'runs' (fans turning etc) but i am not getting any display to my monitor from the graphics cards.
ive tried having one card in, with/without external power supply all the different combinations you can imagen.

am i doing somthing wrong or have i got conflict somwhere?

make sure everything has the proper power running to it, video cards specifically.

also, memory causes boots like this also.. so try it with one stick, and see what happens.

the video ports its usually one to the top side that is active, and on card 1, not card 2

check and recheck power and cables. its something small that you missed. its always the case usually.

Is your monitor plugged into the top graphics card? You could try booting with one stick of RAM and see if that works. Make sure the 4-pin power connector is plugged into our board too.

i tool one ram out, no difference.
checked my 4 pin connector it was in, but i noticed another 4 pin right next to it.
connected that in and i got a signal (green light on monitor) but nothing else, no txt.
put the other ram back in and now im getting no signal again no matter what i do

make sure that u have the power cord either a 6pin or a 4pin that goes into the power supply next to the ram for crossfire

i changed the ram to different slots each at a time, now its working i can see txt ect.

if i put the ram back in will it break again?

it shouldnt and if it does it states that one of the sticks maybe bad, or your mobo isnt getting enough power.

make sure got all the connectors in.

the 24pin, and then the 8pin next to the cpu, and any additonal 4pins you might have on that board.

i got everything installed, and put the other ram stick in.
no matter what port it put it in, i dont get any signal to my monitor (on its own or with the good stick).
The good stick works in every slot.

btw when it isnt working, all the fans stay at maximum speed (you know when you turn the power on all fans go on for a brief second) until i turn it off.

i guess i have a faulty ram, are there right and wrong ways to go about it to get a new set?

If they were part of a set I think you have to RMA both, meaning you'll be waiting on RAM and won't be able to run your PC for a while. Otherwise, just live with one stick and maybe buy more RAM later and hope that works.

that really, really sucks

yeah i know. sometimes, just sometimes its helpful to have the place you are buying it from do a post test.

yea, sounds like a RAM error. I had this same exact thing happen on my HIS 4870s upon installing them on a new rig. The fans revved up, but no post screen. Found out it was a badly seated stick.