excuse me, im newbie and lets go to the point.. 
several days ago im build my new rig on a new case, finalished it.. then try to turn it on. the problem start when i turned on the pc, monitor said "no video input" "entering sleep mode". im so confuse here cause i never xperience this.. i've checked all cables, fine and cool. all other peripherals are working fine, lights come up, but no display on monitor.
anyone can help me?

several days ago im build my new rig on a new case, finalished it.. then try to turn it on. the problem start when i turned on the pc, monitor said "no video input" "entering sleep mode". im so confuse here cause i never xperience this.. i've checked all cables, fine and cool. all other peripherals are working fine, lights come up, but no display on monitor.
anyone can help me?