Did you connect the status LEDs from your MBs to your case?  Those LEDs help with troubleshooting. No, didnt see any.

Sometimes the PSU has a switch to go between 120V or 240V.  Check that. How?

Does your MB have built in vga or DIV-D output?  If it does, try removing the video cards first and plug into MB's own monitor ports. Dont have any built in

Remove one of the video cards and CrossFire link.  Treid with only 1 from the start

Is your monitor on?  Set to the right input?  Don't laugh.  I've seen it happen before. ;-) Checked and double checked. Monitor replay "going to sleep"
 

Ja, mener det.
Har sjekket og dobbeltsjekket alle tilkoblinger.
Kan eventuelt ta noen bilder og poste her om noen tror de kan hjelpe?
Begynner å lure på om prosessoren kan være defekt?

Tried all 5 PCIE slots on motherboard, no luck :-(

my parts are:
Motherboard: Gigabyte GA-990FXA-UD5, Socket-AM3+
 
2 cards: MSI R9 280x
 
PSU: Cooler Master V850, 850W PSU

Ram: 16GB ddr3 ram

Kan se og høre at vifter, hd m.m. starter men der er ikke noen "output" til skermen. på skjermen står det "no input, going to sleep"

Plz hjelp :-)

Yes, it seems so.
Fans on graphic gards starts. Also all other fans and HD.
USB and sata ports got power.
I have no clue what I have done wrong :-(

Hi.
I am trying to build a rig to mine:

my parts are:
Motherboard: Gigabyte GA-990FXA-UD5, Socket-AM3+
 
2 cards: MSI R9 280x
 
PSU: Cooler Master V850, 850W PSU

Ram: 16GB ddr3 ram

I can se that it gets power when start up, but theres no output to my screen. Its says no input, going to sleep.

Any ideas whats wrong?