Asus rampage ii extreme motherboard build (first)

hi every1 i need some help please, this my very first build n im stuck now
heres my spec :
Mobo : Asus rampage ii extreme motherboard
CPU : intel 920 core i7 2,66GHZ
Memory : Corsair dominator 3channel 2GBx3 memory card
GPU : (1) BFG (GTX 260 Maxcore 55nm) OC
PSU : Corsair 1000Watt modular PSU
HDD : (1) WD black cav 1TB hdd
optical drive : Pioneer DVD R/W
Case : HAF 932 fulltower case
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i have done all the step in (ASUS rampage ii extreme) user book, n i just plug all major part n cable :
- cpu installed
- cpu headsink installed+fan
- soundcard installed
- memory card installed
- gpu installed
- all case fan installed
- front panel n usb from case installed
- hdd installed
- optical drive installed
- PSU installed (24 pin to mobo, 2 pci-E to GTX260 OC GPU, 1 extra cable to power up the hdd n optical drive) im sure all connected as the manual book show me
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Next out of the case :
- power plug (Wall >> PSU) plugged
- power plug (Wall >> monitor plugged
both ready to power on
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1st try : i plug the DVI-D (male n male) cable its come with my monitor (alienware OPTX 21" monitor) to tge (GPU : DVI-I female VS Monitor : DVI-D female) n power on the cpu n monitor
- 4 fan (case) working
- 1 fan (cpu) working
- asus ROG logo light is on n other Led on motherboard is on (bios led : on) (sata port led : on)
- GPU fan working
PROBLEM IS : the monitor pop up the message say " no signal"
- then i try all the source "HDMI 1 , HDMI 2, DVI-D port from monitor (not working)
- first i thinking theres something wrong with my monitor n try with my old pc it working,
MAYBE i missed some installation step ? anyone please help me with this problem,